Are my fears of being too old to persue my dreams realistic?

Hello everybody, I am a 20 year old man from europe.

I have a question for you all that has been weighing on my mind for a couple of days now and is really bringing me down because I fear the answer. First a little backstory.

In high school I was a kid who liked a lot of things but could never choose which thing he liked most. One thing I knew for sure though, I did not want to follow the same path as everyone by doing something as rediculous as studying. I was sure that I would be able to forge my own path on my own way. This matter of rediculous thinking only came back to bite me in the ass a lot later. Since I was put in a lower niveau of highschool (don't know how to call this in english) basically the school for kids who would grow up to get mediocre jobs.I was fine with this and even proud of it. My inability to focus on a subject which I wanted to study played a very large role when I enrolled into college.

I switched from college 3 times because I could only focus on the things I did not learn instead of the things that I would. Because of this I ended up wasting 3 years of my life. It's a story that I am very embarrased about because my personal development was basically at zero.

After these three years, of which the last year I decided to work without a diploma to figure things out I learned how much I missed school and learning new and interesting things. I also discovered my one and true love, biology.

Next year I decided to enroll into the college that would take a screw up like me and had a lot to do with biology. Here I now study to become a biochemical analyser.

When I finish this study I will be 23 years old. I want to follow this line and develop myself and go into the medical field. But where I know for certain that I will be able to do it, I also fear that by the time I finish this more advanced study I will be 27 years old. I fear that I will at this point be too old to be able to get a job because of how much I would cost and how little work experience I would have.

I guess my question is this:
Could I follow the study path of my dreams and only be able to work, and generally start (by lack of a better term) grown-up life?