Hi OP, a good friend of mine has AS. He was diagnosed at 19 and is now in his early 40's.
There's a huge range of difference in what people with AS experience. His has been quite severe (and his doctors agree). He had vertebrae in his spine surgically fused in his 20's, which limited his range of movement (he limbo dances in and out of his car for eg) but this was apparently better than allowing the condition to continue untreated in his case.
He did test positive to the gene involved (I can't remember which gene it is). He's also had eye problems, but nothing more severe than having to wear glasses and get the scripts changed a bit more frequently than usual.
It affected his working life badly- in that he can't stay in one position for very long & it's hard to find a job that allows him to keep moving as you need to or take breaks etc. And of course the longer that goes on for, the less employable you become... he largely lives off govt disability payments now. Not for lack of trying.
Otherwise he's quite active and lives pretty normally. Exercise is crucial to his well-being; over the years he's found swimming and tai chi the most helpful for him. He's been involved in various clinical drug trials over the years- it does seem that AS is being researched & work is being done to improve outcomes for people.
I don't mean to freak you out by saying all this! Truly his is a severe case that's been ongoing for 2 decades. It seems many people like yourself aren't diagnosed until later in life; whether that has an effect on severity, I'm not sure. He says (like a PP) that it's known to affect men worse than women.
I hope you've got or can find a true specialist to assist you with this- it's a condition with plenty of on-going research and new drugs/techniques to try but you do need an expert to help navigate through it.
Very best of luck to you :)