the age of innocence

I was just doing a rather long run in the rain over dale and down dips in t'country, and for some reason started pondering the loss of innocence of my small girls.
Yesterday I met up with an old friend who has girls aged 9 and 11 - I hadn't seen them for a long time and so I'd forgotten what older girls are like. In fact, I have no idea really anyway - because I don't know any one much older than Mol. These girls are tall and gorgeous, and behave much older (obviously) than my little gals, with uptodate technology and knowledge of popular-music and they communicate in a way I'm not familiar, and y'know, are just more grown-up.
I was quite in awe of these girls (and vainly wondered what they thought of me) and then I turned to see my little Mol, who - still in a bubble of frank-innocence, Father Christmas features big and so to does the strange fairy who collects teeth at midnight and the concept of magic is way-believable - didn't basically quite know where to look as these exotic girls gyrated (in a slightly off-hand-way) around the kitchen to tz-tz-tz-pop muzac with an air of experienced-coolness.
I wasn't sure what awed me the most.
Was it their confidence with technology that I barely understand? - non-chalently thumbing through their tunes on the ipod? Was it the skinny jeans and jeggings? Their language? Body language? That they were taller than me (not difficult I admit)?
Or was it the fact that one day, very soon, my little Mol (and following shortly on, little Liz) would be thumbing her way over her own i-whatever, bopping in time to pop tunes which I've just about heard of and feel much disdain for?
And I wondered, as I skidded over some cow-pats which decorated the bumpy Hampshire tarmac, how long exactly is it that we have, as a family, before that gorgeous innocence - the belief that magical creatures DO exist, and that Dad really CAN do magic with cards, and that £40,000 is probably not much more than £40 or £4...?
Whilst we have been staying in Hampshire this week with my parents, my two girls have been hanging out with their cousins - a boy aged 6 and another 4 year old...
And what merry times they have had. Running around the garden playing "Cheetah's" and "Lions" and "Babysitters" (Ok, so I'm 21, you're 18, Liz is 2 and Cherry is the baby... and I go out and leave you and Cherry starts to cry because her nappy is  pooey, ugh! poo! ... - I mean, these games can go on for DAYS...). And then after a healthy supper of pasta and pesto and chocolate icecream and pringles they all jump into the bath together - having first run around the upstairs unclothing themselves willy nilly room by room...
No one notices that the clothes have come off. No one comments on the bottom (unless conversation turns to farting or poos but that's not in a self conscious way - maybe Liz has done a massive fart so lots of hilarity and fake farting follows...) or the lady bits or the boy bits. They just jump in the bath and carry on with whatever game they had been playing, but naked and surrounded by water.
And as I panted my way up a very steep hill through the pretty hamlet of Ramsdean, I wondered, will Mol WANT to have a bath with her boy cousin next year? She'll be 8.5, he'll be just over 7 - will they be too old to share a bath? I'm pretty sure I didn't have baths with my brothers after they were exiled to prep-school aged 7 & 8... (me being 5 at the time...)
And then I remembered, as I rounded the corner of the steep hill, to see that I hadn't yet reached the top and had at least another 300m to go, puff puff, that when we, as a young family - me (aged 8), my two brothers (10/11-ish) went to the South of France - mum had sort of strongly encouraged me to not buy a bikini top and just wear the bottoms -and I remember feeling mortified by this and totally self conscious and wanting to hide and not go to the pool in case all the boys saw my (nothing to reveal) flat as a pancake boobs. But I did feel embarrassed, and I remember that feeling so well. Please. Don't. See. Me. (I did swim but spent a lot of time in the water as opposed to standing on the edge doing dives...)
So, as I limped my way into the last mile of my run (legs a bit leaden I must admit) I came to the conclusion that we may not have very long before our childrens' bubble of innocence is popped and Mol decides that baths with cousins aren't such a fantastically fun idea and that she'd rather spend her time gyrating around the kitchen with an electronic gadget listening to some teen-hunk-crooner.
And playing "cheetah's" is a bit last year? 
So now I feel a bit sad and wonder if we moved out of London now, to a remote coastal hut in Wales, we could extend the period of innocence till they're both about 15?
Or would that be a bit weird?