I can see where you are coming from and rightfully so. But if you pay attention to the story there is a need for all of this. Denise starts as someone very shy and gets her new found self esteem and anxiety tackling approach from the relationship with the MC and her sister.
So realizing that this helps her dealing with her anxiety and self esteem she keeps pursuing this with maximum effort. Hence the pushy and bossy behaviour. She can't afford to fall back in her mental state from before.
While this helps maybe explain why that is, it does nothing to make her like more if you don't like such ppl or behaviour of such ppl in general. Yet i hope you can find it in you to continue this wonderful game and the amazing story and enjoy it to the fullest as the rest of us does.
I'm not question her motives. In fact, her motives for being the way she is are irrelevant to my opinion of her. For example, when you want to go outside and play ball with your friends on a chilly day, and your mom insist that you put on a coat. Her motives aren't harmful, but that still doesn't make her insistence any less annoying.
And I'm also not seeing what you're seeing in terms of her tackling (or dealing) with her anxiety (at least not through Chapter 4). If you don't make choses that are in line with what she wants (i.e. she doesn't get her way), her anxiety goes up. That's not tackling anything IMO. People with anxiety tend to have this need to be in constant control, and when they feel like they are not, they go into panic mode. This is exactly what she does, and is the bases for most of the characters' actions in the game thus far. One of the main challenges for people with anxiety is letting go. Not having things that are out of their control effect them in a negative way (emotionally). I'm assuming this starts to change for Denise in Chapters 5 and 6 (I haven't gotten there yet), because, right now, I'm not seeing any of that.
All I see is a pouty, pushy brat. One with genuine, heartfelt, motives; but still a pouty, pushy brat none the less (there are just to many negative consequences to her not getting her way).
And don't think for a second that my opinion of Denise is a critique on the game, or is having any negative effect on my enjoyment of the game. It's actually quite the opposite. Think about how well written this story is for me to spend this much time explaining my opinions of a character as if I was talking about a real person.