Ease answer soon definite 10 points!! (Travel Ryanair)?

Ok soo my aunt cousins and nana are going Dublin Luton later this month and I am supposed to go with them but we didn't know until a week ago and now we realize that I am too young to fly by myself.... so I can't book a flight on my own but I really need to go with them or another airline that will take me on my own but i'd rather not so is there any way to book their flight on my own (it won't let me get past finding the dates!). To conclude I need to book my cousins flight but I'm too young to fly alone. Help!!!