As far as goals, I don't expect to be a strong contender, but I'd like to eventually be respectable, say 7 or 8 out of 10 on average? Not sure if that's possible. Really I just want to compete and have fun. I know there's other precision disciplines, but I like the excitement of prs type shooting
That is a perfectly attainable goal and you don't need a pile of gear to attain it.
I'm almost 67 and am affected by significant lumbar osteoarthritis and a couple of other physical limitations. I can't "run and gun" either, but I enjoy PRS matches immensely.
You have a rifle and scope entirely suitable to try a match or two. TRULY - you do NOT need to buy a pile of stuff to try out the sport. Far and away, the best investments you can make - whether you compete or not - are a decent bipod followed by a single bag. It's hard to go wrong with a Harris HBRMS (swivels notched legs, 6-9") bipod and a GameChanger (or similar) bag. Total for the two, new, is well under $250 and you may well find them cheaper on sale. Beware knockoff bipods. Just sayin'.
You'll also want to learn to use a good ballistic calculator on your phone. I have tried several and prefer Strelok Pro, which is a screaming bargain at like $12 in the Apple or android app store. There's a whole section here on SH about them.
In my experience, 500-600 yards is enough range to develop your skills for competition and to learn to use your ballistic calculator. I have easy access to 550 yards, which is where I spend the great majority of my practice time. Less often, I'll drive 80 minutes to the 1000-yard range to which I belong. I will say that 800-1000 yard targets are more difficult for me in wind and mirage conditions, but really most of the targets in matches are 300-750 yards.
Honestly, where I see the older guys struggle is in flexibility. You don't need to be a yoga instructor to shoot PRS, but you do need to be able to go prone from standing, and perhaps back again, while on the clock. Getting comfortable in a kneeling position with bad knees can be a challenge. Shots that are too high for kneeling but too low for standing can try old joints and tired bones.
@hlee is right about flexibility but it isn't a show-stopper. I have limited range of motion in my right knee. It takes me a relative eternity to go from prone to standing an kneeling is out of the question. I think there was one stage of one match where kneeling was required for part of it. The RO just let me stand for that piece of it. I practice to find workarounds for props which challenge my range of motion limitations.
I've been shooting all my life and competing for half of it, but precision rifle competition started for me in summer 2017. I took a couple of classes, the second of which was a day-long 1x1 where the instructor and I worked on how to best approach PRS-style positioning with my physical limitations.
What he told me, backed up by my experience in several PRS-style matches since then, is this: if you know your rifle and can hit targets at various ranges from comfortable positions, you're already ahead of the 20-30% of people who show up at matches and don't know their rifle well.
If I go to a regional match and place in the upper 50th percentile of the typical 100-120 entrants, I've had a very good day. Even on days where I finish toward the 75th percentile, I have a good time, and typically I did something really silly along the way (examples: dial wrong elevation setting, engage targets out of order, can't FIND a target because I wore a tinted lens that made it disappear, leave my chamber flag in on a mounted-start prone stage....).
If you go to a match, and especially if you have access to a range where PRS shooters practice, you should definitely feel comfortable (courteously) approaching shooters and asking questions. One range where I compete offers wrist bands to new shooters, so ROs and squadmates are more "hands on" helpful. Many people really helped me out, lending bags and other bits to try as I came along. More than once, I have spent the majority of my range day helping a newbie. As others helped me.
Enjoy.
Here's a curve ball for your interest: rimfire and rimfire PRS-style matches. Then 300 yards is a gracious plenty, where a gnat fart or stray cosmic ray moves your bullet....