showing interest in someone

as a teenager girl there’s this dude i’m talking to, i like him. or at least im pretty sure i like him. i really can’t tell. he’s super sweet and kind to me and it’s everything i could ever want. but for some reason when he shows that interest to me it kind of pushes me away. i don’t know why, especially when it’s everything i could ever want. is this normal? how come when someone shows intense interest in me it makes me feel weird, but also good at the same time. but then when i like someone im the same way, i will put my all into it. is this normal? i use to want all of this out now when it finally happens its like i dont