Should I be concerned if she takes a long time to respond?

Let me fill you in. I am good friends with her and yes she has been my “crush”. I always text her if she’s had a bad day and stuff. But recently she’s been taking 2-6 hours to respond to me sometimes. For example last night we were playing game pigeon at a good pace and then she just stopped. I texted her this morning at like 10am just about some good news she would be interested in and no word yet. I know she got it because it said “delivered”, and from what I know it’s only when you open the messages app and look at the text is when it appears at “read” so she potentially saw it as a notification still.

I get she might be busy but she’s usually not like this and she just got a new phone to but she’s usually not like this.

Is this a good things? A bad thing? Maybe this is like a cryptic thing girls do that I don’t know about or I’m just overthinking. Maybe the few girls on this subreddit could help me out thanks.