I expected to feel nothing given my older age and my relationships in the intervening years, but once again I am victim to all the symptoms you describe. When the lessons had run their course, it was forgotten and life went on as usual, but I recently resumed lessons with him.
He's a teacher of mine, who is about 10-15 years younger than me and the crush first occurred many years ago. I am currently suffering from one myself. I am 58 and heartened to know other women my age are capable of these infatuations. I find it particularly shameful as my behaviour is of the sort I would have condemned had I been told about a man with sexual feelings for his pretty daughter-in-law. Other older women have said how attractive they find him so maybe there is something about him that triggers these feelings and it is not entirely my fault.