WHO's BORN IN DEC 8 (male saggitarius)2002

and accidently fell in love with May 27(female gemini) 2007 i know she's still young but i don't know.. everytime i'm close with her she gives me butterflies in my stomach.. I KNOW OUR AGE GAP IS 5yrs but i really don't know why i fell in love with this kid and INFACT she's the same age with my sister.. i feel so weird falling in love to a girl who's 5yrs younger than me and even HAVE THE SAME AGE as my SISTER🤦🏻i don't think this is normal right now.. WHAT SHOULD I DO???!! it's not normal anymore..