As a 43 year old, there are times when it gets a little harder to learn sometime quickly, or finish all the suit as fast as the next person. However, I am more discerning, I noticed. I don't just pick up random frameworks/libraries/things as much, and when I do I have a descent sense of if it will work for me pretty quickly. I also like to say "What makes me a senior engineer is that I've forgotten more than you've learned". :)