I think there is no thing as overworking you butt muscles but more your glutes and your knees because the more often you work out the bigger the risk gets to hurt yourself! So wehn you start working out you might be like "hey only my legs hurt why doesn't my butt ?!" but don't worry you will see after a little while that it affects your butt too!
I started with the saat challenge which was very hard at first but then i got used to it :) 3 times a week would be good with a rest das inbetween :)