It was good, but you could have done a lot better. I think your personality was lacking from most of the effec and the patter was say-do-see patter.
Patter first. You TWICE say you are not performing magic but an experiment. First off, why bother characterizing what you are saying? Second, an experiment makes me think of High School science class which isn't a very magical image. Third, later in the routine you say "this is where the MAGIC happens." Wait, I thought it was an experiment? If you want to call it an experiment, carry this through the patter and make it mean something.
Your patter is say-do-see all the way. I do this, you do that and look what happens. And, despite the fact that lots of magicians tell you to do it, recapping doesn't help your magic. You build this great suspense and then essentially start telling people what they saw 30 seconds ago. This doesn't build suspense... it kills it. The only time to recap something is if you have to plant a memory (e.g. saying that the spectator shuffled when they only cut the deck). Recapping is not necessary here.
Now for your personality. Where is it? The say-do-see patter strips "you" out of the effect. You need to script the effect and have a number of one liners and jokes built into it. You then need to be able to respond on your feet.
There were lots of opportunities for witty responses. Someone in the audience yelled out "I love you." It was clearly a guy. My first response while watching was that you should have yelled back "I love you to, MOM." Your spectator was wearing antlers (or at least that is what it looked like). No matter what you say about them it would have been funny, "what is your name deer?" or look at the antlers and say "all of a sudden I feel underdressed" or even looking at the antlers and asking "those are fake, right?" You also were getting some "what is going on?" body language from her during the point where you pull the card into your mouth. Again, a perfect time for a line such as, "I always get that reaction" or "don't knock it until you try it" or even "tastes like chicken." Those lines you could have scripted and use as needed.
As for scripting, here is what I would have done (off the top of my head). First, if you like the experiment idea, go with it. "I want to do an experiment in chemistry and I need a volunteer. A female volunteer. An attractive female volunteer. No, not the guy in the fourth row..."
Ask the volunteer's name. When she says Katherine, introduce yourself. "I'm Michael and I'm your date for tonight. We are going to do an experiment to see if there is any chemistry between us." If you don't use the chemistry angle, you can say, "I'm Michael and I'm your date for tonight, we are going to see if there is any magic between us." If she smiles, you say "I think this is going to work." If she pulls back or give you a what are you talking about look, say "I can see we are off to a good start."
Have her pick one of the blank cards. Tell here to "pick any card you want." While she is trying to pick a card, move the deck side to side. She will hesitate and you can say, "it doesn't matter, they are all the same." Pull the deck back and fan it again. As she picks one, say "not that one! Just kidding."
Then come up with a justification for writing her name on the card. "I have a problem with names, once I actually forgot the name of my date. To prevent that from happening, Elizabeth, can you write your name on the card?" She will correct you and tell you her name is Katherine and the audience will laugh. When you take the card back say something like, "usually I have my dates write their names on stickers so that they can put it where I can see it (hold the card where you would put a "Hello My Name Is" sticker) but I think instead that I'll have you just fold it up and hold on to it." You make the first fold and have HER make the second fold. Hand the card that is folded in half and tell her, "fold it up so it is in quarters." This will give the impression that SHE made both folds.
After she has the card in her mouth, ask her a question. "Are you starting to feel the chemistry (or magic)?" Whatever she says it will be funny because the card is in her mouth. If she says no, say "Good, because we haven't done any magic yet."
"Now at the end of my performances, spectators always ask for my autograph. Would you believe sometimes? Occasionally? Well, I performed for my grandmother last week and she asked for my autograph."
"Just in case you forget later, I'm going to sign a card for you now. I'm going to do the same thing you did and fold up my card and put it in my mouth."
"Now I need you to look in my eyes and do exactly what I do... Wait, this is awkward, isn't it? It would be much better with mood music." Again, this is funny because it is awkward but the music makes it even more awkward. The music needs something different - more romantic like corny over the top romantic - like the theme from Titanic. Have her do exactly as you do and bring the card into her mouth. I think your expression during this part doesn't work. You need to shift from humor to serious magic as if you are focusing on making the magic happen. The best way to get the appropriate expression is to say a script to yourself like, "I'm going to take the card in my mouth, close my eyes and it is going to change places in 3,2,1 and now I open my eyes." Your expressions will follow what you are saying to yourself.
"Did you feel anything?" If she says "No." Your response is "then can you explain how this (open card) got in my mouth?" If she says "yes" you respond, "There must be a connection, because how else can you explain how this (open card) got in my mouth?" Then hit them with the finale, "if you card is in my mouth, any idea what happened to my card?" You know have the audience WANTING your card to be in her mouth.
This isn't meant to tear you down, but to help you build something better.
