Yes, it could be a problem. Every person must be accounted for.
If you call to make your reservation, indicate that one member of your party is under 3. When you pre-pay, you will not be charged for the child under 3 but the child will still be accounted for in your party.
If you book online, I believe that if you assign your child’s profile to the reservation, it will know you have someone under 3 (because of the child’s birthday in the system) and you won’t be charged but the child is still accounted for.
Do not show up without adding your 2 year old to the reservation one way or another. Every person, no matter how young, must be included in the party count. It’s how they stay within capacity.