Yes! Your Authereum account is 100% decentralized. You are free to do what you want with your deployed contract based account with or without any Authereum services.
If you are using the Authereum website and services, you will be able to use some features that are centralized for convenience. Authereum provides these services to help ease the process of using cryptocurrencies. If you do not want to use any of these services, you are free to do everything on your own without any centralization or censorship from Authereum.