It makes a difference if they are prem, but not late.
If they are prem their organs may not be developed enough yet.
WRT instinct, all instinct can tell you is that your baby is hungry, it can't tell you that your baby is ready for the chnage between milk and solid food.
DS2 is a bit older than your DD, soph.
He is 23 weeks, but he isn't ready, he puts everything in his mouth, he protests if we take it away from him, he won't BF if anything is going on around him. Because he is at that stage developmentally, it's not actually to do with food.
They are more active and more interested in things so unless starving, they'll feed as a last resort. Everything seems much more interesting to them than lying still feeding!
Also, this is the oral stage of development, where they explore things using their mouth. Anything and everything you give them will get put in their mouth because it's how they explore the it. With texture, taste, temperature etc all worked out by their mouth. It's just coincidence that they do it with food.
You say she still sucks it at the moment so that in itself says she isn't yet ready, or she would most likely chew, rather than suck. If she was ready she would be physically able to eat unaided, i.e. sit up, pick it up, put it to her mouth and then chew and swallow, whih is why BLW is suggested. That way you could still give her bits of food, but allow her to go at her own pace and you can be pretty certain that she won't be eating early.
Apart from that, with all the risks involved why would you want to rush into something that she may not be ready for? Especially when you say you can't be bothered!lol.
I'd stick to what you know will satisfy her, and keep her as risk-free as possible, which, IMO is BLW. So, fine, give her pieces of food to play with when you're eating, but don't feel the need to feed spoons of mush into her where she can't make the decision herself.
HTH
(Tis VS btw)