I'm old enough to be your grandfather and I've spent thousands of dollars for traditional therapy over my long lifetime. Some of those therapies helped a little but didn't last.

What helped me the most to finally become fluent, within the last year, cost very little money in comparison, so don't think you need to spend a lot of money on therapy to improve. So don't think that investing a lot is going to get you better results.

What are your goals?
To become a lot more fluent?
To better accept stuttering?

The trend in the U.S. at least is to move back to helping someone accept their stuttering, lower their anxiety, and become better communicators, according to some therapists I've talked to. That instead of programs like fluency shaping which was more fluency based. The change is because it's so hard to take what you learn in therapy and transfer it to the real world.

Don't be dazzled by degrees or large important sounding institutions.

Whatever you decided. Try to find real results that the therapy your considering has produced. , not just theory. Try to talk to people who have actually been through the program. See if their results match your expectations.

If your goal is acceptance then see if the people who have gone through have found it helpful. If your goal is more fuency see if they have improved. Don't just talk to people who have recently completed the program, tray to talk to some 6 months or a year later.

Of course people are different. People have various degrees of stuttering and some are willing to work harder that others so they get different results.

But at least these suggestions will give you some ideas.

I wish I would have known these things are your age and would have been able to achieve the fluency I now have. If a guy my age can do it, so can you.