Hi!
You have a couple of options! 
I have colleagues who also have children in the building. They actually prefer to have two separate accounts (one for teaching, one for parenting!), for their roles in Canvas. They use their official school email for their teacher account, and they use a personal email for their observer account. The most common feedback is that they can separate work life from home life a lot easier. They can sign in to Canvas Teacher and Canvas Parent using the appropriate login credentials and set notifications in a way that works best for them and their family!
If you'd like to keep your accounts "merged", you can use your teacher account to also observe your child. When you click Account then Settings, do you see an Observing tab? If yes, you can follow the directions in this guide: How do I link a student to my user account as an observer? If not, let me know. There is a way to do it, but it's hidden. I'll send you the workaround in a private message because it can also be used by students to observe other students.