Is 23 to old to start training for mma ?

I’ve done jitsu for about 8-9 years now and also competed fair abit as well and it’s done me a world of good but I’ve been wanting to compete in mma for couple years now but I just think I’m too old to do it , Specially when you guys saying that they started when they were kids.

My second question is what is the way to go about it too. Specially when you’re at a jits only gym and been really close with owners since my early teens , taking classes and helping around the gym for so long now.

Like do you leave jits gym for a mma gym or do you do both at same time? Almost feels like betrayal in a sense going to two different gyms.

Please share you’re thoughts , thank you