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
You can check the status on the Monetization tab of YouTube Studio. The majority of channels hear back in less than 30 days, so be sure to look out for an email or Studio notification from us! More here: https://yt.be/help/YPP-review