Leaving baby when she sounds frustrated

Is it ok to leave my baby in her bassinet for a little bit in the mornings when she sounds frustrated but she's not crying? She's 2 months old.

I typically let her lie there and babble/make noises for 10-15 minutes because she seems to be entertaining herself. Eventually she gets a little frustrated and I still don't pick her up, just in case she goes back to entertaining herself. When she starts to whimper a little bit, that is when I pick her up and start talking to her.

Am I waiting too long?