Not being a citizen will not count against you. As long as you have the right to work in the US, it doesn't matter where you were born. A Masters degree is better than a Bachelors, so you are in good shape there, too. If you wanted to work at the commuter airlines, I would say that they would prefer to hire someone a little younger, but they are going to be desperate for pilots in the coming years, in my opinion. The "flying to the islands" type jobs are very much "not what you know, but who you know" so I don't think that age would matter there at all.
Good Luck!