It was ok. You should re-work your patter a little bit, the student thing was random. Also, you flashed when you were revealing the 4 aces. That is the amazing part of the trick when the cards change, and you want that to be as visual as possible. Try and make your movement more natural, too. But other than that it was good.
I think you should work on a different trick. One that's actually worth the effort!
If you are interested in this kind of effect - a twist then a change - then take a look at "Maxi-Twist" taught on Bill Malone's "On the Loose" DVDs or John Guastaferro's "Tailspin" taught on his "Brainstorm" DVDs. Mercury is just. not. good; the versions I recommend are far superior. Actually, while you're at it consider taking a look at David Regal's "Cheating" which follows similar lines but has an extra couple of phases for very little extra effort.
Don't feel defensive - I'm not critisising you, just the trick you're performing. Sure the performance could be improved but that's true of everybody - we all improve by taking on board constructive feedback and then doing more practise. Best of luck in your magical endeavours!