"wallet_account_register" registers your account on the blockchain, both for users and delegates. It does register a normal user by default, though.
But no worries, you can update the registration of your account using "wallet_account_update_registration":
>>> help wallet_account_update_registration
Usage:
wallet_account_update_registration <account_name> <pay_from_account> [public_data] [delegate_pay_rate] Updates the data published about a given account
Updates the data published about a given account
Parameters:
account_name (account_name, required): the account that will be updated
pay_from_account (account_name, required): the account from which fees will be paid
public_data (json_variant, optional, defaults to null): public data about the account
delegate_pay_rate (uint8_t, optional, defaults to -1): -1 for non-delegates; otherwise the percent of delegate pay to accept per produced block
Returns:
transaction_record
So in your case, for a 3% delegate and assuming "nicocesar" will pay for the registration (remember, it costs 2 weeks of delegate pay to register):
wallet_account_update_registration delegate.nicocesar nicocesar null 3