I'm 12 and in love with my bf but people say that's not possible why?

My name is Marissa and I am in love with my boyfriend Lee. He and I laugh and drink milkshakes and walk and talk all the time about our pasts and everything else. he is my soulmate and i can't wait until we get married one day. we argue a lot but we always come back together and when we're making love i know that we will always be together. everyone's being negative and mean though saying we can't be in love because we're 12? isn't that dumb? you love who you love, doesn't matter your age, right? i am so sick of everyone being a jerk about this