Is having "too much youth" in a fantasy dynasty league a bad idea?

I'm playing a first-year dynasty league on Yahoo, a 10-team (yeah, I know, get out) 6x6 H2H.

There's a majors draft and a minors draft for minor leaguers (who qualify even if they've already made an impact in the majors: the threshold is either under 100 IP or 300 AB). Minor leaguers have to be moved onto the actual team roster once they surpass the threshold otherwise they become FA after three days.

In my majors draft, I mostly went for younger players with ceiling and picked up older guys only if they fell down the order (Dye, Dempster, Carpenter). I picked at #9 and #12, and I got Grady Sizemore and Ian Kinsler. Afterwards, I dealt Kinsler and Jermaine Dye for Phillips and Hunter Pence. Opening Day team ended up as:

C: Martinez

1B: Berkman, Loney

2B: Phillips, Hill

3B: Davis, Encarnacion

SS: Drew

OF: Sizemore, Pence, Bay, Ethier, Werth, Burrell

SP: Billingsley, Zambrano, Nolasco, Liriano, Josh Johnson, Wandy, Dempster, Carpenter

RP: Lindstrom, Francisco, Wheeler

Then came the minors draft, where I was picking #5. Because of a drafting error I made in not recognising Davis being under 300 AB's until about twenty picks later, I was lucky enough to have Davis reserved for me at #5. Afterwards, I picked:

Bumgarner

Cahill

Alderson

Holland

Morrison

Jennings

Main

Max Ramirez

Motte

Borbon

Beltre

Cunningham

Boscan

Tucker

As you've seen from the list, Cahill and Motte are already up in the majors, but I have plenty of time to wait and see if they pan out until they hit the 100 IP limit. But I'm a little worried that with all these guys bound to show up, I already have a bunch of young talent at the positions. Not sure about Martinez; Berkman will be replaced by Davis who'll probably lost 3B-eligibility; Phillips will be there; 3B might be a question mark; Drew will be at SS; Pence, Sizemore, Bay, Ethier will form a long OF; Loney, Werth, Hill will round things off. Pitching-wise, I have Billingsley, Nolasco, Johnson and Liriano and maybe Zambrano all ready to pitch plenty of strong innings. The other guys should be pretty strong back-up, and Wheeler will probably be dropped once the TB closer situation sorts out and Motte settles down.

And so the question here is: did I go overboard in drafting younger players and thus block whatever my minor league system may produce? Or it's a win-win situation in that I can contend for years to come and use my farm system as assets to pick up guys for a championship run? Or is all that irrelevant and I should be able to turnover quickly enough to accomodate?

What would be your strategy of running a dynasty league with minor leaguers?