There is no age restrictions at all, as far as i know, People coming from Pakistan are getting Visa on Arrival without any problem. Just keep your Polio Certificate with you, a return ticket, Yes Immigration does ask for either Hotel Booking or the Address where you'd be staying, Just ask your Uncle for his RP Copy, & his address just in case immigration asks you these questions...
Rest you are good to go,
Just update this post regarding your VOA experience...