The same thing happened to my daughter around the same time. She got sick of pureed foods in a real hurry, (well . . .wouldn't you ?) LOL. We just had to find ways to slowly add finger foods into her diet a little bit at at time and now she self-feeds herself finger foods only. It means having to give her fresh food and mashed up or cut up steamed veggies all the time which I find is much more work but probably healthier. I started with cheerios, and once she got used to it we slowly added new things with new textures. I also gave her some rice rusks as well to start b/c they basically melt in her mouth. I agree with pp, sometimes giving them some finger foods gives them an opportunity to get distracted so that you can get in a few mouthfuls of pureed, but that only worked for a little while until she caught on. My dd did the same thing with the spoon too, gagging herself, I just bought all soft rubber spoons so she could stick it in her mouth and gag on it without causing damage to her gums, she learnt not to gag herself eventually. She will take a small amount of rice cereal if I give her a spoon, but soon realizes taking it with her hands and sucking her fingers is much more efficient and the spoon ends up on the floor. Be prepared for a major mess each meal, the floor, the high chair and your lo, so I just lay garbage bag on the floor, take all of her clothes off except diaper and end up basically hosing off the high chair each time she eats. But you know what, it is so good for them to learn about textures and fine motor skills. Sounds you like have an little independant one as well. Good luck and let me know how it goes.
