When should I tell this man I really like him?

I am crushing really bad on a teacher at my child’s school. He is a teacher of the same grade my child is in. He has flirted with me from day one and he always strikes up a conversation when we are standing in line at flag deck before the bell rings. I can totally tell he likes me, he has even told me how pretty I am before right in front of the other teachers. Being a teacher though, I think he wants to be careful. I am an adult though and he is an adult, so is there anything wrong with me telling him I like him? I cannot stop thinking about him and when I leave after seeing him, it feels like such a big part of me is missing because I’ve been putting off telling him. The weekends are hell too because that is two full days I don’t see him. He’s so sweet too to my son. He loves him and plays with him during recess, and it isn’t even his student. =) This is the last week of my son’s school before he’s out for a week and I won’t see him for a week. I’m thinking about telling him now, on Friday when my son gives out Valentines for an early party, I’m thinking I’m going to give him one (so it isn’t so obvious to the other teachers, I’ll be giving them one too -from my son) but in his, I’m going to let him know how I feel. Any advice? Thanks! By the way, even if he turns me down or says he is in a relationship, which I am almost certain he is not… I will feel better to at least have gotten it off my chest.