Is it possible to become hard after 30?

I spent the majority of my 20s not doing much due to anxiety and depression. I won't get into details but my 20s feel like one major black out. I got sober from alcohol 6 months ago.

My question is, who has experience in changing and becoming "hard" after 30? My brain is wired a certain way now for 10 years just doing nothing. Now I realize this is the only way I'm gonna be able to have some real mental clarity and change my life.