Hello there, most channels hear back in less than 30 days. Each application is manually reviewed, so it does take a bit of time! Hope you hear back soon – in the meantime, here’s a bit more info about the review process: https://yt.be/help/YPP-review
We don't have specific timelines to share – we suggest for you to check out the AdSense help community. You can find FAQ’s and answers regarding AdSense issues: https://yt.be/help/2Vdb . Hope this helps!