Indeed, this experience is the best teacher. from experience we will learn many things. and of course we will try to be better. and do not repeat the same mistakes.
I am never against experience and indeed there is a lot you will always get to learn from experience in the long run anyway. For instance, you cannot compare someone who has been trading successfully for 30 years to someone who is just starting out to trade, as there are so many things the former would have learned over the years of trading that the newbie is just getting to grasp.
Nonetheless, even as much as experience is the best teacher, I have never seen someone with a professional experience not having to learn first as that is one first stage you do not want to be living out.