I'm 40 myself and playing in a competition semi-final today (as long as I'm selected in the 22 :mellow: ) and there are about 4 older guys than me in our team. It's possible to play especially if you're fit (I'm average at best with fitness), but as goodNumber10 said after a few bumps and knocks you'll know.
Perhaps only going through the contact stages of training initially and seeing how you go with that? If you're fine with that, contact in games is generally harder, but not massively so.