Personally I actually think you will gain a better understanding because you have nobody to teach you.
If you work with people who are already experts, they will always prevent you from making mistakes. Being able to actually make those mistakes gives you a much better understanding of why people do things though.
I wouldn't say that... I'll often put in "for next time, look at..." type advice in Pull Requests from more junior coworkers. Sometimes working is more important than ideal.
It's when a Junior-Mid dev has to add a feature that's made difficult by their own choices and then rethink to make things better they tend to learn. That said, plenty of Jr-Mid devs don't advance with more practice, they stay jr-mid.
If you work with people who are already experts, they will always prevent you from making mistakes. Being able to actually make those mistakes gives you a much better understanding of why people do things though.