It looks very simple, but somewhat cool to me. I like it! What I would add to it would be a mini logo of your group icon or game icon if its going to be added to a game.
I was honestly a little confused at first due to coins being round however taking another look at it this is unique and has it’s own style to it! I love it. If there was one thing I’d do differently I’d maybe try adding something in the middle so it isn’t to dull.
Looks really good! Maybe you can add a small letter in the middle of the coin or something. Like if the coins are called R coins, you would put a nice R in it. But overall looking good!
Although simple, I think it looks great! The outer ring is well proportioned relative to the size of the coin and really helps emphasis the cartoony design. As @Roboritech and @Valkedd have suggested, I think an icon, letter or number on the inside of the coin would be a nice addition.
If I were to offer any suggestions for when you eventually import the final model into Roblox Studio, I think adding some subtle glimmering particle effects would help to draw players attention to the coin and make it look even more valuable.