Cuzin? I fear the genetic damage of your coupling is already taking effect. Even though you're not actually related. Stuff like that can happen. I once winked salaciously at a pigeon and I was struck dumb for a whole moment.
It's normal and totally okay to date anybody who is age-appropriate and not related to you, as long as y'all are happy together. If anyone has a problem with it, it's their problem.
Also, it's cousin not "cuzin"!
It's not like it's your own cousin - although that's legal too.
If your friend doesn't like it .. too flippin' bad.