Is she into me? or it is a bestfriend thing?

ok so i have this best friend who i met at college 4 years, im a but didnt really come out to anyone untill about a year ago or less and ive been gau since 16 and im now 21 anyway, i fell quite hard for her...and ive never been able to tell her because i dont know where it will lead, abit worried about our friendship so ive kept it on the low and ive tried everythin to try and get over her but nothing is workin, but only recently as in the last couple of months she's been giving me mixed signals but she says she;s straight and keeps saying i do believe her but its these little signals i get from her make me think hmmmm is it me or is she into me? is she just being really nice and thats how she is but ive known her for ages and she'e never been like that before so im wondering whats goin on here anyone give me any ideas thx :)