What happens when an Alliant Teen Checking Account holder turns 18? The Alliant Teen Checking Accounts will automatically convert to a regular Alliant Checking Account once the accountholder turns 18. The existing joint owner(s) will continue to remain as joint owner(s) unless they are specifically removed by the primary owner. We'll send a new debit card, which should be activated as soon as possible. The debit cards for the teen account should be shredded, as they will be deactivated shortly after the teen's birthday. At account conversion, the daily ATM Debit Card spending and withdrawal limits will be increased to the regular checking account limits.