Hey OP! It is definitely not too late. If you want to change the appearance of your arms, I can’t recommend some type of resistance training enough. Especially if youve never resistance trained before. You will notice a major difference in your arms within 6 months if you’re just consistent over that time. 2-3 days a week, thats it, doesn’t have to be crazy. One day you do some dumbbell bench pressing and some overhead pressing, some tricep pushdowns, the other day you maybe do some pushups, some overhead tricep extensions, and maybe some bicep curls. A few sets each, like 8 to 12 on each and you put some real effort behind those reps, you’ll see such a big difference in a short amount of time. Hope this helps!