Almost 3 years ago something flipped in my brain. I felt similar to you for many years before that. At the time I was obese, so I worked on that first. Eight months later I was still overweight but significantly stronger and healthier.

During that time I saw how I had limited myself at work because I didn't feel confident enough to ask for more. During my annual review at work, I made it clear that I felt undervalued. My employer eventually responded, but it was too late. I had already started seeking a new job.

I interviewed at a few places and I took the highest offer, even though it was the least interesting work. That job allowed me to work from home and gave me a lot of solitary time to reflect. Even though I've been programming for my whole life and I earned a great salary, I had never gone to college. It was a regret I had held for many years. For the first time it was possible to go to college, because of the flexible hours allowed by my job as a telecommuter. So at 34 years old I started taking classes at my local community college.

Fast forward a year and a half, I quit work and transferred to one of the top computer schools in the country (top 5 in EE, CS, and CompE.) Sometimes it feels strange to be 15+ years older than my classmates, but then I remind myself that it's never too late to achieve my goals.

The last couple years have been the best years of my life. I have no more regret because I am doing everything I can to realize my potential. It's never too late.

TLDR: Be honest with yourself. Reflect, Analyze, and have the confidence to pursue your dreams.