How do i ask her out?I love her but idk if she feels the same way..?

im in 6th grade and iv know this girl whos gave me butterflies since 3rd.I honestly wouldnt go for another girl knowing visioning myself married with her.But shes the kinda girl that says she loves someone for a month and then another guy the next...Since I have these feeling about her do you think she would have the same?we havent talked in awhile so i feel like she doesnt know.Im young but honestly this has to be love because im cocky and crazy around other girls..around her im shy have an adrenaline rush and dont really make contact with her and i blush.Its like im on cocaine around her..is this love and do you think she feels the same way plz help