When to text back?

I’ve been talking to this girl for a while now. I tend to test back quicker, maybe taking 10 mins if she took 30 etc. Just now, she replied to a text I sent like a half hour ago and I replied within 2 minutes.

I already had my phone in hand and just said what the hell, why not respond?

There is this modern culture of being nonchalant and chill but I AM chalant. I don’t want to wait 30 minutes to respond to look cool but I also don’t want to be overeager/smothering.

Do you think texting back too fast is bad? Does it feel smothering? I know she actually likes me but I’m still hung up on whether I should slow down a bit or not. What do y’all think?