Hello Ariella!
Welcome to SAAFE. I am not a larger lady, well, I will be if I carry on scoffing, but I have a couple of friends that are. Like all things, if you have the right attitude you will do well- there are lots of BBW fans in the UK, in fact I think its a bit of a niche.
You can set upper or lower age limits, its your preogative, but remember that it is the older clients who tend to be the pussy cats, the younger can be a pain in the arse who like to show the local prossie how its done so to speak, so you may find yourself reversing that policy, but as I said, its up to you. Speaking for myself, over 48 is my bread and butter, however I am older than you.
Not much sexual experience will be an asset to you with some clients, and a detriment with others as they may be looking for a swing- from -the- chandelier -while- sucking -my bits kind of escort, but if you make it clear from the outset that you are new to the industry that should take care of that.
I must warn you in advance though, this isn't a job for the feint hearted or thin skinned. If you aren't already very confident it can actually knock your confidence, or on the flip side be very empowering- and there really is no telling how you will cope until you see your first client.
As always though, good luck!
Lucy x