Brooke Shields still feels like a 38-year-old.

The 52-year-old actress has admitted she doesn't put herself in the 50 plus age bracket as she only associates the milestone with ''older people'', and she believes she is almost 15 years younger than she actually is.

Speaking to PEOPLE, the 'Army Wives' star said: ''Because I don't feel that age. Fifty sounds like it's for older people. I'm stuck at like 38 or 42, max. Fifty is a terrifying number for some people.''

Although Brooke - who has Rowan, 14, and Grier, 11 with her husband Chris Henchy - believes she is in her late thirties, she has noticed ''everything'' has become ''exponentially harder'' as she has matured.

Brooke - who dated the late Michael Jackson when she was 13 years old, and the artist was 21 - continued: ''And I finally found out how to set myself up to succeed. But I still need to commit to it. And everything gets exponentially harder the older you are.''

As the 'Pretty Baby' star has gotten older she has stopped making New Year's resolutions because she used to set herself up for ''failure''.

Speaking about what has changed about her over the years, she said: ''When I was younger I looked forward to making resolutions, and as I've gotten older I've realized I don't want to make them, because it makes it such a one-off. I would pick something and I would sort of set myself up for failure.''

Brooke has now vowed to uphold a ''certain quality of life'' throughout 2018.

She said: ''So instead of 'I'm going to lose five pounds' or 'I'm going to give up chocolate,' I make this promise to keep upholding a certain quality of life throughout the year. I do like the idea of a fresh start, but it's about trying to keep balance.''