My DS is the same! He's 7months and really can't handle much at all in the way of texture. I've started giving him home-made porridge from oats that I chopped in the blender till they were fine and then cooked up. The resulting porridge is finely lumpy but the lumps are soft. It's a handy way to get him to take texture without having him gag (I HATE it when one little lump from something is enough to make him gag and bring up the ENTIRE contents of his stomach
). We are very slow getting started with solids - we've been at it for over a month and he's just not interested so I guess he hasn't had much practice with textures either. Friends with babies the same age are already feeding their LOs bananas etc broken into little peices, not even mashed - I've just had to tell myself that DS will get there in time but not soon!