is that a good rating and is that the best game mode for a beginner


It's good progress. The time control is up to your preferences. There is no one answer that works for everyone.
What are you doing to improve?

Hi! My name is Lauren Goodkind and I’m a respected chess coach and chess YouTuber based in California:
https://www.youtube.com/channel/UCP5SPSG_sWSYPjqJYMNwL_Q
You might want to play with a slower time control, such as G/30 so you have plenty of time think before each move.
Here's some other tips I can give you:
-I recommend two books for you: “50 Poison Pieces” and “Queen For A Day: The Girl’s Guide To Chess Mastery.” Both books are available on Amazon.com. Both books are endorsed by chess masters!
-If you are serious about chess, I highly recommend you hiring a chess coach to help you.
-Also consider all checks and captures on your side and also your opponent’s side. Always as, “If I move here, where is my opponent going to move?”