NYC things to see for a 16 yr old?
 

We plan on taking our 16 yr old neice for her 1st visit to NYC Dec.26, 2017.

Any advice on where to take her, things a 16 yr old might find interesting? She's from VA. We are doing a day trip only.

I have no idea what this particular 16-year old might find interesting, but in general, I'd say a walk through Central Park, down Fifth Avenue, and through Times Square would fit the bill.

Wollman Rink in Central Park might be good.
The Christmas markets at Bryant park and the rink there (if still open after Christmas).
Store windows at Macy's, Saks Fifth Avenue, Bergdorf Goodman, Lord and Taylor...all usually gorgeous.
Serendipity
Maybe Sea Grill or Rock Center Cafe for lunch...especially if she will want to see Prometheus status, ice rink and the Rock Center Christmas tree
Eataly might also be fun to check out (esp if weather doesn't cooperate) --several food counters (including gelato) and restaurants within Eataly
Not sure how long the day will be but Lincoln Center for The Nutcracker or a Broadway show
Chinatown has all kinds of fun, quirky stuff

It's hard to answer the question without knowing what her interests are.

https://www.thrillist.com/lifestyle/...liday-calendar

Christmas markets definitely and the Lower east Side tenement Museum.

Ellen's Stardust Diner.

Does day extend into evening? If so, walk down Fifth from 59th to about 47th.

Since she’s 16 ask her what she wants to see and then plan an itinerary from there. Particularly for a day trip you ha e to focus on what’s really important to her.

Top of the Rock

Alvin Ailey as well as Nutcracker
pastries at Austrian cafe near museum (76th and 5th?)
Tenement museum
Ellis Island passing by (not stopping at) Statue of Liberty
And, yes, give her a guidebook now and ask her if she'd like to shape a day for herself and you'll follow.
If there's snow Central Park and making snow angels