Have you read "Reassess your chess" by jerry silman? Its a great read.
First tournament

Are tournaments open to beginners? I play daily, but I don't know any openings, and I've only read one book on the subject. My reason for trying is to find out my rating, although I don't want to be completely humiliated. Any thoughts? I'm an adult beginner with children that also play and we're about the same level.
I think that there are 2 main restrictions to playing daily tournaments - one is that you must have completed at least 5 online rated games on chess.com (you have played over 100 online daily games so you don't have to worry about that)
The other is that you must have a timeout % of no more than 10% to play in tournaments. Your daily time out percentage is 0%, so there is no worries there. https://support.chess.com/customer/en/portal/articles/1444863-who-is-allowed-to-join-a-tournament-
The only thing is that as a free member you are limited as to the number of tournaments you can enter and you can't create any yourself. https://support.chess.com/customer/en/portal/articles/1444843-how-do-membership-levels-free-vs-premium-affect-access-to-turn-based-tournaments-
Apart from that, you should have no problems in joining tournaments.
As for finding your rating, for daily games it is 901 on chess.com https://www.chess.com/stats/daily/chess/mrspatrickwheeler so if you are looking for tournaments you could play those that are rated less than 1000 if you like. Of course there would be nothing stopping you from entering open tournaments apart from the normal restrictions for free members.
If I have completely misread your question and you are talking about live tournaments - sorry I don't know much about them because I don't play them, but here is a link that might help: https://support.chess.com/customer/portal/articles/1444927-how-do-live-tournaments-work-where-can-i-join-one-
More information about daily tournaments: https://support.chess.com/customer/en/portal/topics/620388-tournaments/articles

That's not completely true. Chess.com's tournaments tend to be limited to those who have a track record. Other daily tournaments are not.
When you look at the daily tournament list, one of the filters is "My Tournaments." It isn't a list of the tournaments you're entered into but a list of the tournaments you can enter. Feel free to jump in.
But you aren't limited to tournaments for determining your rating. Any rated daily games affect your rating. So just go to the Daily page and start a game. The bad news is that your rating won't be accurate after playing one game. The more games you play, the more accurate your rating is.
If you look at your full rating ("Stats"), there's a bunch of information there. One of the numbers is your Ginko RD. It's basically a confidence interval. Your "real"rating is most likely within the range of your calculated rating (the one on the web site) plus or minus the RD. I started with an RD of 350. It's now less than 100.
Outside of tournaments, I tend to limit the players I play with to ratings +/- 100 of my rating. (I've seen advice that you should play with people up to 400 points higher than your rating, and no less than 100 points lower than your rating. But I don't like losing significantly more often than I win.)

Thank you for your responses. Although I was thinking of a USCF rated tournament. Is our chess rating similar to what our elo rating would be?

USCF tournaments are open to beginners. The main requirement to play is membership in USCF; for some tournaments, your state might also require membership in its chess organization. And then of course there's the tournament entry fee.
I have to disagree with the book recommendation in #2: Silman's "How to Reassess Your Chess" is indeed a good book, but if you are a near beginner it is too advanced for you. Something like Irving Chernev's "Logical Chess Move by Move" would have far more instructional value at this point. For other suggestions, chess.com member @RussBell has put together this helpful blog: https://www.chess.com/blog/RussBell/good-chess-books-for-beginners-and-beyond
Good luck to you and your children!
Are tournaments open to beginners? I play daily, but I don't know any openings, and I've only read one book on the subject. My reason for trying is to find out my rating, although I don't want to be completely humiliated. Any thoughts? I'm an adult beginner with children that also play and we're about the same level.