As one of those people who's doing vet med in their 40's - I say never put your life on hold.
I've done some really amazing things in my life, had two different careers, and am now in vet school at 40, because I said "yes" when an opportunity came along, instead of waiting on the sidelines for the "right" one. As it turns out, going through the doors that were opened to me, instead of banging my head against the one's that weren't, ended up being the absolute right choice.
Does my life look the way I dreamed it would when I was young and starry-eyed? Nope, and I'm perfectly ok with that. I wouldn't trade my crazy, amazing, wild ride of a life for anything. And I'm not done yet. Not even close.
So I say have faith and go through the door that is open for you. It will take you where you're meant to be - and it will be better than the place you thought you were "supposed" to go.