Bag size on limousine bus (Okinawa Bus Lines)

Hello! In a couple weeks I will take the limousine bus operated by Okinawa Bus Lines from Naha to Moon Beach Museum Resort. When booking it said that maximum bag weight is 10 kg. This seems very light, considering this bus departs from the airport. Most people must have bigger luggage, right? My main bag will probably be around 15 kg. Will this be a problem, or am I good? Should I arrange to have the bag delivered instead?

by Breadl0afers