Does he like me? or is he just kidding around?

so there's this guy and we just met this year (we're in high school). I have one class with him. at the beginning of the year we didn't sit by each other but he told my friend he thought I was hot and asked her for my number and now he comes and sits by me and my friends most of the time instead of his friends. we made plans to hang out a couple times but he had to put them on hold because he had sports. we would joke around and flirt a lot in this class. so he asked this other girl to homecoming but that was before we really new each other. but I don't know if he likes her. so this is where is gets confusing. he calls me babe or beautiful to get my attention. one day he told my friend that I was his girlfriend and when we went to lunch he came up to me and put his arm around me and told everyone at the table that I was his girlfriend. then a couple weeks later said the same thing. except he said he was going to ask me out (he said it jokingly) at lunch but then he was like I can't hold it in will you go out with me. and I said yes. and it was a big joke. he did throw in that he was serious but still. then we were looking at these magazines and there was one of these funny babies and I said something about "my future kids" and he was like you mean "our kids" and telling me that we were going to travel the world together. then after class he grabbed my hand and was like we're officially going out now. and he held my hand for a second. then he went to my table where I usually eat (I wasn't there) and one of my friends told me he said something about me being his girlfriend and him asking me out. so does he really like me or is he just kidding around? oh and my friends all warn me to be careful cause he's a player and just wants to get into my pants. should I listen to them? and one friend (a boy) always tells me these bad things he's done. so is he just jealous or serious? (I know that friend has liked me before) sorry I have so many questions I'm just confused.