Help me someone? problem with a girl?

ok so im 17 and this girl has been texting me for a while. she has been texting me all the time and its getting a bit annoying for some reason. she i a nice girl and everyone is calling me a wimp because i wotn ask her out. i dont really fancy her because well im a boy and i know this is gona sound wrong but i want sex when in a relationship and she is really fridgid. like when were at school she is talking to me she gets really nervous and has been so nervous she has been sick in front of me! i think thats mainly the reason i dont want to go out with her because she is so fridgid and shy. but all her friends think its me that really likes her for some reason and i want to tell her i dont like her but im not sure how to do it and if i do do it her everyone will say im a jerk because i "lead her on". help me someone???