What if the person only entered the field at age 35? I'm not sure physical age is relevant. Also, many people, myself included, find the thought of working at the management level highly distasteful.
If you entered a field at 35 (appear 35) when most of the peer group in the company is 21, you are going to have hard time getting hired for same role being performed by 21. If the company that expects/has most 40+ employees in management, you are going to have hard time staying in technical role unless you have built bridges with management that want to keep you around.