I wouldn't read into it too much.  People are curious beings.  We want to know about other people, because we look for similarities between ourselves and others.

Is it impolite to ask one's age? No, not in my book.  If one has a problem with the question, they can decline to answer.  It's perfectly acceptable.  There's no need for one to take offense.    

I think it really depends on what the context of the questions were.  For example if this was during a lesson or language exchange, I would think it was a fairly normal question.  It's an easy question to ask/answer.  If this was in a initial message, then that's a bit more odd, although it probably was intended as an innocent question.  

However, I"m curious what kind of question about your appearance were asked.  That seems a little strange to me; after all you have a profile picture, so what questions are there to ask?  Unless it was during a lesson or language exchange and he was trying to get you to talk more -- hair and eye color are also easy questions to ask and answer.