becky - we started BLW at 23 weeks, although DS really didn't eat much to start with. I was leaving food on his highchair try, and he started when he was ready. (He could sit pretty much unaided and obviously had the motor skills for it)
Immediately he was spitting out the bits he didn't want - for example, pear or courgette skin (which hold the bits together better). I've always been amazed at how good he is at getting what he wants down him, and rejecting what he doesn't.
It can take a long time for a BLW baby to have their dinner - its not 10 minutes for a few spoons of puree - they have to work for their food. However I have a 9 month old baby that eats all sorts of stuff - including noodles and spaghetti, baked beans, peas - all with his hands (we use a spoon for yoghurt and a doidy cup for soup, but he controls them all!)
DS gags sometimes when he gets too excited about what he's eating, but has never comes close to choking (although he's been sick after gagging perhaps twice in the last nearly 4 months). With the exception of the time the vomit went up his nose, he generally laughs (I don't know why its funny but apparently it is - maybe I make a funny face or something while he's gagging) after he's cleared his mouth and puts more food (often the bit he's just gagged up!) in his mouth.
Just enjoy it. If your DD is ready, she'll eat. When she is she'll eat at her own pace.