I am with you 100%. I LOVED mine between about 3 and 15. Had the best life with her. SO much fun and games and laughs and day trips to theme parks, zoos, beaches, picnics, wonderful Christmases, and lots of crafting, swimming sessions at the local baths, cycling through the countryside, going to the cinema, watching TV, going to pop concerts, playing singstar karaoke on the playstation, playing footie, rounders, cricket, hide and seek, video games, building snowmen, doing the rounds with gifts at Christmas to relatives and friends, school trips, school plays, painting, feeding the ducks and swans, drawing, going for walks, reading and writing, the works.
Those twelve years or so were wonderful with my DD, and took me back to my own childhood a lot. I miss these days terribly. She is in her mid 20s now, and has her own life and career and partner and home, and lives 20 miles away. Me and DH see her twice a month, but rarely socialise with her now, as she is busy with her friends and career, and it makes me a little sad inside. But I know this is just life. You only have your children for a short while.
I guess that's why God created grandchildren. One day!
(maybe.... She does want kids but not til she's 30.)
And I agree that age 14/15 to about 18 was quite difficult. For reasons many people have mentioned.