I just cut the apple up - into quarters and then halved those it that makes sense. DD was eating apple like that from about 8 mths, I think (also without teeth). By about 18 mths she was eating a whole apple raw (much easier than even doing the cutting!). I've seen plenty of other toddlers who've done BLS eating whole raw apples even younger.

The only thing my DD ever choked on doing BLS was a stringy piece of mandarin at 18 mths. She gagged, coughed it back up, looked at it and then popped it right back in! I think if you've been giving her normal food, rather than purees, she will have learnt how to handle the different textures and manage her food better without choking. I heard all of these choking hazards well after my DD had eaten all of them perfectly fine!