Yes! TextNow is for everyone over the age of 13 and is available for download for iOS and Android devices, as well as your laptop or desktop computer.
When you download TextNow, you will be provided with a real 10-digit phone number that you can use to call and text your teen and get to know that app that your teen wants to use to communicate with their friends.
Read this blog post about the benefits of having a second phone number if you already have one!