This will seem really odd...?

So I was stupid back in high school. lol. I liked my government teacher. I had cl with him everyday, and I used an excuse to talk to him through the school's email, and told him I had a huge crush on him. He simply just replied back what am I supposed to say to that? I have been out of high school for four years, and I did some just random looking on the computer found this teacher on Linkedin, should I request to add him? Is it inappropriate? I know he's not married, and I think he's still single... I'm just wondering if he would be a little freaked out that I found him on their and requested him, or if he would even still remember me, Idk. What do you think?