Is it normal he is all over me now that i am 18?

I turned 18 not that long ago....like a week ago and suddenly my teacher is all over me. The day before I turned 18, he asked when my birthday was, and the day after i turned 18, he asked to talk to me. Now he acts weird and always seems to want to be near me. Dont get me wrong....I love it because I have had more than crush on this teacher for 4 years now. But, i didnt think he would start acting right away. He treats me differently, always finds a way to talk to me, always looks at me in class, flirts with me, touches me (not a dirty way either, just the hand or arm or something) and just acts different to me now that I am 18. I feel like since im an adult now, hes gonna try something. Is it normal?