All Grown Up With No Place To Go

Something happened the other day.  It was the point in my life where I think I officially became a grown up (there is a substantial difference from being an adult and being a grown up I think)
My 26th Birthday is approaching, and my Mother asked me what I wanted for my birthday.  Usually the answer to this question is something along the lines of Puppy, Trampoline, Shoes, DVD’s, CD’s, Stereo, iPod etc. Fun stuff. Stuff that you can play with. 
My response this year was Shampoo.  I no longer have the urge to put in orders with Santa for fun stuff, just items that are essentials so I don’t have to buy them for myself. 
When did this happen? When did I become all dull?  Should I accept that the carefree fun of youth is well and truly behind me? Or should I go and drink goon and play ping pong with my teenage friends? 
But perhaps I am stressing prematurely.  I was shopping in the toy section of Target for my 3 year old Nephews birthday and was awestruck by "The Wizard of Oz” Barbie Dolls.  Please feel free to present me with one on my birthday.  Many Thanks.