How old are you? If you were like 15, 3 years is a big difference. If you're 28 or so, 3 years isn't so bad. Also, you failed to explain their qualities. If it were me, and if I didn't know what the girls acted or looked like. I would choose the same age.
Yeah, it you're under 16, you really don't need to have a girlfriend. As Flippin and Cheetah have stated, pick the one the suits you best. I currently like someone about three years older than me. BUT we have absolutely have NO plans till after we are both done with school.
Well, without any more information I'd say Victoria. She's in the same grade as you and the same age. That means you are in the same mental space, with the same issues with regards to teachers etc. Also opens the possibility for you sharing classes, which is always a plus. Though if Magen is in the same grade as you as well... the same applies.
If this would be your first relationship I would suggest further that you go with whoever you feel most at ease around. In other words, who ever is your better friend. Being able to carry a descent conversation while on a date takes a lot of the pressure off.
...you don't deserve to go out with a single one of them. That may sound mean but dating is over rated; I myself am tired of seeing/hearing about people dating just for the sake of dating because "its fun". When you date just to have fun, let me tell you, it only rots your soul.
Date the girl who is helping you out, friendly to you, and is more than eye candy.
I agree with NoName, you should pick the one who is genuinely nice and you know pretty well. you need to be good friends before you start all of that dating business.
Anyways you have your answer. Having to pick a girl that you want to go out with is not "trouble" in the case you present to us. Therefore I am locking this down. Any further discussions may be done under yout profile comments but I am ending it here.