Emergency Exit Rows

As can be seen in my signature, we have booked our second trip to Hawaii for next year. On our last two flights (LAX-JFK-LHR) we’re in Economy Plus, but we’ve been given emergency exit seats. Now I want to know if there is an age limit for these rows? I’ll be 17 at the time of travel, I wasn’t sure if you had to be 18? If so then we’ll have to get on the phone and see how they’ve made the mistake.