Ahh school, your first glimpse into life in a penal colony.
1) Don't expect ANYONE to like you.
Sadly, as you are a freshman, you have just been given a status slightly below vomit. It's not your fault and you did nothing to deserve this. It's just one of the joys of high school.
2) Do not attempt to interact with older students.
See reason 1. If they interact with you first (preferably in a non violent manner) you may speak to them.
3) Yes, that older girl is the most stunning creature ever to grace God's green earth. No, you have no chance, no shot, no possibility of EVER interacting with her.
(Obviously, if you are female, reverse the genders in the above statement)
4) Your best bet is to treat it like prison (or work); keep your head down, do what you're supposed to, and count the days till it's over.
Everyone older than you was in exactly the same position as you, and if they're picking on you, odds are someone picked on them.
No one wants to be the last person in line when lousy behavior is being handed out.
5) Remember, next year, you move up on the totem pole. Older students will speak to you, you still don't have a shot with the Senior girl, but the amount of crap you're expected to take diminishes greatly.