Maybe join a club first. As you can see from some of the posts above plenty of people will happily let you have a go on their rifles. Aintree Pistols in Liverpool used to be good, having some troubles at the moment, but if they get the issues sorted try them, indoor, open week nights and Saturday afternoons. Atherton indoor range (AIR) also good.
I started on a springer, now have springers, CO2 and PCPs, I would highly recommend starting with springers, they are harder to shoot, so are a very useful tool to develop proper technique, if you can shoot a springer well, you can shoot anything.
Most important considerations are fit and trigger. My TX fits me really well, finger just goes to the right place on the trigger, feels heavy but balanced.
The weight is important HW99 is great if your carrying for hours, but you will notice the recoil more.
I run a lot, I have a slow strong pulse, I notice with any gun the pulse bounces the rifle slightly, the HW99 bounces a lot more than the TX - not an issue if your trigger pull is between heart beats, but interesting.
I have a pair of 30 year old BSA Superstar underlevers, lovely capable quality guns, as accurate as my HW98, HW99 and TX200HC, but the trigger is nowhere near as good, this makes them much harder to shoot well. If I get the trigger right its pellet on pellet, but the "surprise break" is much harder to achieve consistently, the HW and Air Arms triggers are a huge improvement and contribute enormously to consistently accurate shooting.
I am isolating at the moment - partner is in a vulnerable group, otherwise would be making the same offer as the posters above.
.177 or .22 doesn't matter at all if your shot is in the right place, I use mainly .177, but .22 on rats at close range.
Air Arms, Weihrauch, BSA, Crosman, and Baikal