Hello.
Happy sims mobile simming! :)
You can’t reset your current game, unless you completely uninstall the app and if you haven’t linked your save files progress to be backed up.
This is a link to guides on playing the game
https://answers.ea.com/t5/Game-Information/FAQ-and-guides-for-The-Sims-Mobile/td-p/6660105
This thread explains how to save your game progress
https://answers.ea.com/t5/Game-Information/Guide-How-to-save-your-game-progress-in-The-Sims-Mobile/td-p/6052342