Too early to potty train? 18 months old.

[TeddyRuxpin]

DD is 18 months old and was given a potty as a gift by a relative at 10 months to start training. Needless to say, I didn't attempt to train her then as I knew she wasn't ready.
I left the potty lying out with the thought that she would get used to seeing it so that when the time came to use it, it wouldn't be a scary new object.
The past month or so, DD has been telling me when her nappies are soiled/wet or handing me a clean nappy when she needs changed. She is dry after naps and she seems able to hold her bowel movements if we are out until she is back in her own house.
Stupidly I demonstrated the potty by sitting a toy monkey on it and told DD that the monkey was doing a poo. Now 9 times out of 10 when DD needs to do a poo she will get the monkey and sit it on the potty then crouch down and do a poo in her nappy then she applauds the monkey and tells me her nappy needs changed.
She won't sit on the potty herself for longer than 10 seconds.
Any ideas how I could get her to sit on the potty? Have tried praising her and giving her books etc to occupy her.

[Solo]

Why not try her on the toilet? she must see you use the toilet, so can associate the toilet with poo and wee, so get her a toddler toilet seat and pop her on it to see how she goes with that.

[TeddyRuxpin]

I have got a toddler toilet seat and as with the potty, she knows what it's for but only sits for 10 seconds or so then cries to get off.

[Dummyhunter]

try buying another potty and getting her to 'copy' the toy monkey - this worked for my dd also l bought her a toy with lots of buttons which she was only allowed to play with on the potty which helped (BTW Morrisons have pottys on sale for around £1 at the mo)