On my basic and infantry courses, I had a handful of "experienced" folks... which made me feel better because at 28 I thought I‘d be one of the oldest.
One lad was in his early 40s, a big stocky fella who owns a farm literally bordering LFCATC Meaford (he‘s with the G&SF). He had no prior military experience, and stuck through SQ (although he bailed for the infantry course, something about the cows needed to be milked -- I dunno how they waited 3 weeks

)
Another, from my unit, is in his late 30s. He was in 12 years ago, and was about to be made up to MCpl when he decided he‘s had enough and quit. Then he came back, picked the same regiment, same trade, and even with the extra years and smaller, smoke-filled lung capacity, he trucks along just fine.
Whats amazing is guys who were half their age, 17 to 19, were falling out all over the place on short morning runs, and there were these two, keeping up with the runs, the section attacks, everything. Made me feel bad, because I don‘t think my performance last summer was particularly worthy of any medals, although I did my best to put the effort in to it (I admit I seriously slack off on the physical side of things and end up paying for it later).
No worries at all. You may have to work a bit harder at the physical side of things, but pain is only temporary, pride is forever. With age comes experience and the right attitude to get the job done with a minimum of fuss.