From being a coach to being a player? (need your input)

I have been helping to coach the a high school football team again this year. The head coach of the team this year is going to join an adult football league in January. He is trying to talk me into it and I'm not sure. I would love to do it but, I think that I might get hurt and the fact that its not cheap. Playing the game would make me a better coach next year. I love the game and I know that putting the pads on again after 12 years sounds awesome. I'm just not sure how my body would feel about it after 12 years. What do you think? Is 30 to old to be slamming your body into others?