Last fall the deck on 14' sailboat cracked. I put some fiberglass/epoxy
around the crack to reduce flexing and stop it from getting worse.

Three weeks ago I put the boat in the water. Today I sailed it for the
first time. I meant to put paint on the epoxy; I thought I put paint on the
epoxy. Obviously I didn't because it has developed a yellow cast. It
doesn't seem any different than when it was new, except for the yellow cast.

Would three weeks of sun ruin it, long term? Or can I just paint it now and
be glad I caught it in time? I know UV degrades epoxy, but have no other
info.
Any advice here would be appreciated.

(yes, I know that putting new fiberglass over cracks isn't the right way to
fix them; but I was going purely for function without regard to appearance.)