If you think medicine is definitely right for you, there's no such thing as being 'too old.' However, you obviously have legitimate concerns, and only you and those close to you who know you can help you really decide- its different for everyone. FWIW, my parents immigrated here in their mid 30s when they were previously docs in India, and had to repeat their residencies/fellowships, basically getting done in their early 40s. They had to work really hard (its harder to do 36 hr. shifts when you're 37 compared to being 27), and deal w/ being with residents 10 yrs. younger and all that on top of cultural differences, but there's no question it was the best decision in the long run. Nobody ever gets everything their way, but if you're willing to sacrifice a little now, you'll definitely get a lot later. However, that decision like I said is ultimately up to you.