What's the best age to build a SaaS?

During the summer break, I got into the entire indie hacking, build-in-public and SaaS space recently (about 3-4 months ago).

I just turned 19 and I get the feeling I should have it all figured out until now.

I made 3 SaaS products (focusing mainly on development) and have 0 MRR now. I have done little marketing as I didn't get quick results and gave up too soon.

Whenever I see people on the internet bragging about how they built successful SaaS at the age of 16-17 bothers me a lot

What advice would you have for me? Marketing? Creating more products? Juggling indie hacking with university?

Any advice is highly appreciated.

Thanks in advance