Guys: what does it mean when a guy does this ?

ok i wanna ask this to guys cuz i realy need a guy's opinion. so im in 8th grade and i like one of my gy friends (hes in 8th too) ok so i really can't tell if he likes me or not an i really want to find out.. ok first thing's first.. he has a bestfriend thats a girl and another really close friend thats a girl but they both have boyfriends. ive asked him if he liked any of them and he sed no but he used to like his bestfriend. he recently broke up with his girlfriend( she broke up with him) and i was there for him , i told him that if he wanted to tlk i was there and blah blah.. ok so the point is , he really teases me alot about my height cuz im really short (4'11) and hes 6'1 /: soooo yeaa.. then i noticed he started to become nicer and started flirting with me nd stuff and that is wat made me start liking him more. he is not a player or a flirt he only flirts and is nice with girls he likes. (thats wat he told me) but i dont know if hes nice or mean to me cuz he flirts, and then hes mean and then hes nice ! it's like what the hell ?! so i really wanna know. oh and by the way, just a few days ago(he was in the most flirtiest mood) he kept complimenting me while we were at the school garden completing an assignment with the class. so he complimented me, gave me many hugs told people we were dating and everything. and then the thing he did that made me question the most was : HE PUT HIS ARM AROUND MY WAIST ! but he walked around the garden with me like that for like the rest of the time and there was one point where he sed "i like ur curves" but i could tell he was just playig around.. before we left one of his friends said "imagine u guys go out" he didnt say anything and i was like noooo ;) haha and his friend continued saying how were we gonna kiss if he was so tall and then he(the guy i like) told me to tippy toe(he had mentioned before that he loved it when girls had to tippytoe to kiss a guy) and called his friend over to show him that it was possible and then sed to himself "she would never go out with me anyways" i heard him say that ad then he told me but i stayed quiet... what does this mean ? does he really like me ? is he just a flirt ? is he trying to take the next step ? or does he just see me as friend ? oh ! and also lately a few days after all that happend he started getting mean again but yesturday he was really nice while talking on the phone. what does he mean ? /: plz help guys ! (: thanks!