First - make sure you're using the latest version of Audiomack which includes the latest birthday picker design. This makes it easier than ever to enter your birthday and get into Audiomack.
Watch this short clip of how to enter your birthday when signing up or logging in to Audiomack.
If you're still having trouble, please submit this form here and include a screen recording like this one so we can understand where you're getting stuck. We will help you access Audiomack and update your birthday properly.