Cheddar, looks like I am in a similar situation to you surfwise. I started surfing late in life at 55 in 2008 and since late last year have been trying to go from white waves to green waves which I find difficult. Most times I either cannot get the board moving enough by paddling or the tail of the board tips up and I slide off. I can sometimes catch a small wave though that is just about to break, sort of green when I catch it but white before I get up.
I too find it difficult to go out back a lot of the time, if I duck dive I get thrown back to where I started from so cannot get out there. Lying on the board I cannot exactly see where I am in between the waves and after a lot of paddling I think I may have gone out a bit but I look across sideways and can see someone standing only waist deep so I haven't moved anywhere and if anything I am closer to the beach than when I started.
I find the easiest way to go out back is sometimes there is a quiet period for a couple of minutes when there is no white waves and I paddle out before they come back.
I usually surf at Fistral where there are other surfers around and the beach is lifeguarded. I haven't been put off much and keep persevering, after all, looking back it took me 20 sessions before I could even stand up three years ago.
I find that most surfers are usually friendly at both ends of the scale regardless of ability and I wish now that I started years earlier although it wasn't always possible for everyone in those days.
Good luck Cheddar and keep it up.