I'm not sure if you mean in a physical or a psychological way? (re faster development) but anyway physically I would say, no, there is no way Tegan will ever be able to do what some babies can.
While I'm optimistic that she'll walk with help, I know from the way she is now that she will never, ever, in a million years, walk without some kind of aid - and before anyone says I'm being pessimistic, I'm not. She has no feeling in her legs at all, She has her jabs without feeling it, she has blood taken from her heel/toes and doesn't feel it.. For us there aren't just parts of her legs she can't feel, she can't feel her legs.. She has some movement but most of it is just random. She has physiotherapy 4-6 times a day to help her legs get into a better position, but even when her legs are in the right position she doesn't move them. She can hold herself up with her arms (on her front) and has just started rolling over (she rolls over using her arms and her legs follow).
However.. intellectually there is more to her than people think. She seems to be very intelligent, she is always demanding something to do and easily gets bored - she has a lot of stimulating toys and spends a lot of her time observing when we are in a social environment that she is unfamiliar with - on her own she is a very vocal baby but in groups she looks at other children and observes. She's learned how to take the toys from her play gym and throws them at the cat. She calls Boo "Goggy" (hasn't got her G's down yet) and says "Ayey" at OH (her name is Hayley and although T is meant to call her Mum she doesn't lol) and earlier she tried to say Grandad. She copies faces and has realised that when you leave a room, you are coming back.. there are so many things that she is doing that are above her age group.
But I do agree with B - We stimulate our children a lot more because we know there is a possibility they will have learning difficulties (and they most probably will, but they don't always present in the normal ways - some are forgetful, some learn in specific ways, some are introverted and shy and learn through exploration instead of someone telling/showing them things and some simply repeat the things they say a thousand times before they're satisfied) but there is always a chance that its a coincidence - Emma you're doing a law degree so you're obviously quite an intelligent person and I have 7 A Levels.. It could be that our babies have inherited our genes or it could be something we have taught them..
Nurture or nature? Hmm..