I only regret not playing bass in my younger days. I only switched to bass around 2015 yet i have played guitar since i was 14. I'm 44 now. I still have some guitars , just the ones that mean something to me personally. My epiphone les paul , daphne blue strat , telecaster with incredible birdseye maple neck i bought in california , and my explorer that is tuned down to C with 13-56 strings.
Now it's all about bass , i have no interest in playing my old guitars anymore but i just can't part with them either. The ones i could have all been traded in.
I suppose it's a long winded way of saying i regret not starting earlier in my life