what should i do????? he likes me i know it!

Dear anyone who can help me, I’m a 15 year old sophomore in high school. There is this guy a grade older than me…that i can’t stop thinking about. I have liked him ever since i met him when i started high school. I don’t know him that well even but there is just something about him. After liking him all last year he started sorta going after me in the summer we hung out a few times and went to the movies…but when he called i didn’t call him back., and i acted like i didn’t like him and all cool. I KNOW I’M an IDIOT!! When we went back to school in the fall we acted like nothing happened and were just sort of just friends as always with the occasional flirting from him. He then started going out with this girl that was new to our school. But still occasionally flirty with me majorally and then i heard from multiple people that he liked me WHEN he was with her. well about 2 months ago they broke up and we stayed at the flirty friends level. Until one of my friends decides she likes him because he drives now ( and shes one of those girls that will not take no as an answer,very confident,gets what she wants ) Its takin like a few weeks for them to even be together and they are still not “ together” exactly but he was her date for a dnace and she says that they aren’t togather “yet”. But just recently he majorly flirts and like hints he likes me…but then some days will talk about her like she is awesome. But everyone always brings him up to me randomly like im someone that is like with him…and people are like he talks about you alot. Then at the dance he tells me i look beautiful and cuts in with another guy im dancing with but the song is already ending and he says we will dance later…but the last dance he danced with his date but i caught him looking at me and i just walked out. what should i do @ school tomorrow tell him how i feel. He obviously likes me right? love, can’t get him outta my mind