Do you think it's weird that I found my cousin on a dating app?
What relationship do you have with your cousin?
He's my youngest aunt's son. Haven't talked to him in years.
I think your reaction is natural. Anyone would be taken aback seeing a family member on a dating app. Just keep that you found him on the app to yourself.
So I should be quiet about it?
Yeah. There's no reason to create an awkward situation if it's not necessary. You'll maintain good relations with your family that way.