Recoil from a BP rifle
Recoil from a percussion rifle is significantly less than any modern high powered smokeless powder. And a flintlock is even less of a problem. In addition, one of the main advantages of shooting BP is that you can tailor your loads to your situation - less powder = less recoil. Although I doubt that you will ever feel the need to reduce your load to reduce the recoil.
Typically the issue for a new shooter is the noise and smoke; these weapons produce significant amounts of both and it can be distracting. My brother-in-law has a significant flinch that affects his shooting my BP stuff, but he's very good with my Winchester 70 in 30-06. He says it's the noise and smoke.
I'm sure that if you take the time to seek out those clubs in your area that someone will be more than willing to allow you to take a few shots with their guns to experience shooting BP first hand. Buy a few cups of coffee before you buy a gun...