well. 17 years for them(R,J,S,and L) being in Hogwarts. plus 14 years which is how old harry is right now. that's 31 right there. plus you've got to add at LEAST 5 years cause, I mean, James and Lily are NOT going to have Harry as soon as they get out of hogwarts. so right there you've got at LEAST 36. I'm going guess and say mid to late forties though.