Hi Tardis,
I found that as a 13 year-old, I didn't need to do "children's magic" like plastic cups and balls etc. I really enjoyed card tricks that had a sort of story to them, and other kids my age liked that more.
Don't get me wrong, cups and balls is amazing when performed skillfully, but IMHO (in my humble opinion

) my magic is better and gets better reactions when I have a decent presentation or some sort of visual "edge" as it were, that I don't really find in kid's tricks. However, the only thing I still use from a magic set I 1st got, are these two plastic paddles with a fly on each one, and by doing the basic "sleight", you can make the flies disappear and hop around. I just like the reactions I get when I perform this as a sort of "joke" item. I'm actually amazed sometimes that people scream and remember that routine over some of the more demanding tricks that took me ages to perfect. Once, when I asked a kid at my school after a little impromtu performance I did outside, he swore the flies were REAL.
That just goes to show that sometimes the simpler tricks, the so-called "kid's tricks" get the best reactions out of people, and they're really impressed.
So, it's your choice on what you perform, as reactions can be very diverse, but on the whole I think adults appreciate a little more depth when it comes to magic. If you did the same effect on two adults with two very different patters, their reactions would most definately not be the same.
Good Luck in your magic, Tardis!
Fabian.