I'll preface this with I'm not much stronger than you so take what I say with a grain of salt!
There's a proverb: "Urgent before big" that might be useful to know. You play big moves when you should be playing an urgent move defending your corner like Ed showed. Playing big moves is good! It's just a timing issue, you owed a few moves in the corner defending before you get to play those big opening moves. Now how urgent a move is versus how big the alternative is as Ed would say very tricky. This doesn't mean that you always answer your opponent but you weigh up the damage of ignoring their move versus the gains of the move you could make instead, which is complicated and not something I really get get to be honest about it. But defending a corner is *huge* compared to a side extension, so it's an easy choice in this circumstance.