
Flatcoats can be very fussy, I have one here who is eight and still as fussy. The thing to do is not to worry about it, the more fuss you make the worse they get! If you really think she is underweight, feed her boiled breast of lamb, with biscuit, use the water you boiled the lamb in to moisten the biscuit. You could try tempting her with pilchards in tomato sauce, always popular with Rosebud. Are you using a complete feed? I have found that some flatcoats just don't want to eat complete foods. I try to give mine a mixture of foods, so they do get complete feeds but also they have table scraps, fresh meats which I feed raw or cooked, biscuits etc..
As to her season I have had bitches which have not had a season until they are 14+ months of age, and have heard of other bitches not having a first season until much later than eighteen months. So again don't worry about that either.
Go ahead and show her, and enjoy doing things with her. Have you thought about training her for work, obedience or some other doggy sport? Flatcoats love to use their intelligence, as much as we do, and usually take to some form of "work" very happily.
Where do you live? If you live in the south of england then I'd suggest you contact Jill Whitwell and go along to her excellent training group. They cover showing, as well as various other forms of canine sport.
Contact Jill on 01483 416982
Regards
Polly & Foxpath Flatcoats