You're on the back of the drag curve at 39 I'm afraid, but it's not unknown for guys in there 40s to get hired. I've flown with one FO who must have been 45 when employed as a cadet. If you can pass the interview and sim check why not.
All I would say though at 39 and working for Ryanair is I hope you don't have any financial commitments (mortgage and wife + kids) because the BRK pay isn't consistent, good in the summer, meager in the winter. Plus you'll be probably be living out of a bag quite a lot.