As
Goldorak said, it will be ok at OLCI.
FYI, the policy is:
If traveling as a family with children (CHD and/or INF), regular seats will be assigned free of charge.
Customers may select their own seats in advance, however the regular seat selection fee will apply.
A child must be allocated a seat with an individual seat belt and must be seated in the same seat block as (one of) his parents or a companion aged 12 years or older.