Most Helpful Guy
Not at all. In fact, it's actually the norm.
I think the reason why is because girls like the idea of dating an older guy (especially in high school.) Plus girls mature faster than guys, so they may not see any suitable guys in their own age group. Literally, they have to date someone older, just to get someone equally mature to them.
Of course this isn't 100% of the time, but it happens.
Most Helpful Girl
It's only 2 years older. Not weird at all.