I started weaning my 27 week old a few weeks ago, and he is wolfing down food I'm doing a mixture of mashed spoon stuff, purees and finger foods, and LO seems to be in the main enjoying it, and is very good at picking food up from his tray and putting it in his mouth.
However, the one problem we have is that he has two bottom teeth and so tends to bite off bits of food and then doesn't quite know what to do with it in his mouth. For example this morning he was slurping away at some mango and ended up with a small slither on his tongue which he just couldn't get rid of. He ended up getting really frustrated and crying, until he eventually managed to get rid of it an hour or so later!
I've tried offering him water to help wash it down, but he generally refuses it.
Today I had better success with holding half a nectarine for him while he sucked/chewed bits off. Still ended up spitting some out but worked a bit better than him biting off big bits of pieces he picked up himself. With slippery foods like this, I think they can use a little help. He's not overly keen with me holding it, but when it's nectarine, he's all over it!
Other people have said to mimic chewing if they start gagging, so maybe try that if he continues to bite off bits that are too big. And maybe try cooking things longer or make sure fruit is really ripe so that it disintegrates rather than has to be chewed too much. I know their gums are strong, but I think my DS finds some textures too hard at the moment.
I think at this stage (27 weeks today) we're lucky if they get any down them when we're working with anything other than puree. I think it's going to take quite a while before they get really good at chewing/gumming. Meanwhile, they get to explore tastes and textures, which is all part of it.