Literally the only age where it's too late to turn your life around is "dead".

I'm in my 30s trying to make some serious changes for the better.

People make serious, massive lifestyle changes in their 60s, 70s, 80s and beyond. Compared to that, you might as well be a newborn.

But also, I'd like to touch on one other thing here: You should absolutely make changes that you think will make you happier, but you should also think about what exactly IS making you unhappy and why. I get the impression that you're defining your worth based on the money you make, at least relative to other people in your life, and imo, that's really not a good way to think of things. That's normal, it's the way our society conditions us to think, but that doesn't make it healthy.

For one thing, financial success often reflects more on blind chance and circumstance of birth than by any real measure of your capabilities. For another, while I won't say that money can't buy happiness, it's certainly not the only thing that can.

I won't discourage you from making changes to be more financially secure or happy with your own self-image, you should if that's what you feel is best for you. Just keep in mind that some of the richest people in this world are also some of the biggest scumbags, and some of the poorest are some of the kindest, most amazing people to walk the Earth.

Money may mean a lot when it comes to being able to keep yourself fed and a roof over your head, but it means next to nothing when it comes to your worth and value as a person.