Hayden: 43 Days and Counting

7/9/2007 2:46 PM PDT BY TMZ STAFF
Not quite yet a lady, 17-year-old Hayden Panettiere caused neck damage in passersby over the weekend, while hanging out at Nickelodeon Studios in Burbank.

The teenaged red hot cheerleader dropped jaws in this luscious red halter dress and golden heels -- looks like she's ready to move to a more grown-up studio -- Cinemax, maybe?!

When August 21 rolls around, Miss Hayden will be considered an adult, finally able to vote, join the military, oh, and have legal sex. How fast can you count down from 43?