Britney Spears celebrates her '1st birthday' as a free woman

Britney Spears turns 40 today — or 1, according to her fiancé Sam Asghari.

Asghari's measurement comes from it being the pop superstar's first birthday since her conservatorship was ended. For the first time in 13 years, she is in charge of herself.

"Britney feels like this is the first year in a very long time that she actually has a reason to celebrate her birthday," an insider told Entertainment Tonight. She feels like her 40th birthday is a huge milestone, not only in the fact that she is getting older and wiser, but also because she is finally living and enjoying life, along with all the new experiences it has to offer."

And Asghari, who has already taken to calling Britney his "wife" is pulling out all the stops to make this birthday the best ever. He "wants to lavish her with gifts and presents and completely spoil her," the source says. "He's planning on going all out and over the top."

Britney shared a glimpse of it on Thursday and it included fireworks, champagne (that she didn't drink), a mariachi band, a "B" cake and a colorful "happy birthday Britney sign."

"I'm so blessed and grateful !!!!" she wrote.

Britney wrote on social media Wednesday that she was headed "out of the country" to celebrate. Last month, timed with the hearing to end the conservatorship, they visited the exclusive Brando Resort — yes, the Brando — as in Marlon — on the atoll of Tetiaroa of the Society Islands in French Polynesia. It's unclear where she is on this trip.

Britney used to need permission from her father, who was conservator of her estate and in charge of her money, to go anywhere. Her mother, Lynne, described it in court docs as Spears being under "microscopic control." Jamie was ousted as conservator in September and her attorney has accused him of mismanaging Spears's $60 million estate. He's denied it.

After having to ask her dad or the conservator of her person, Jodi Montgomery, for permission to do even minor things — like paint her kitchen cabinets a different color — Britney is enjoying regaining control of her life. She is still supported via a team — including Montgomery, who she kept on staff, as well as wealth handlers — put together by her lawyer.

"Everyone wants to make sure she feels supported and taken care of," the Entertainment Tonight source said.

This week, Britney shared on social media that for the first time in a long while she's on the "right medication." She told the court in June she was treated against her will by doctors, but she's now no longer forced to see the ones the conservatorship made her go to. She said her new medication, which she didn't identify, makes her feel like she's "present."

There are other big changes in her life as a result of her conservatorship ending. She's been able to have possession of her own ATM card for the first time since 2008 — and have access to her money. Before, she received an allowance and people in her conservatorship were given more of her money than she had access to.

She can also drive with her fiancé in the car — and has access to her car keys when she wants them. Before, she needed permission — even if it was to drive a golf cart within her gated community.

While she's been driving by herself since at least June, that comes at a price. She's trailed by paparazzi, hoping to catch her doing something they can cash on — like coming out of a gas station bathroom, apparently. That's what happened earlier this week and ruined Spears's day.

The mom of two teen boys also has babies on the brain, as she hopes to have one with her fiancé, the model, fitness trainer and aspiring actor she met on the set of her 2016 "Slumber Party" video. In June, she said she was forced to use contraception against her will. She was also forced into psychiatric treatment against her will, she said.

Over the last few months, Britney has also gotten her first iPad. She said in August her sons were allowed to have them, but she wasn't. Jamie would reportedly take away the star's phone as a punishment, or permit her to only use a flip phone, if she wasn't complying with his rules.

Among the little things she's been able to appreciate since the #FreeBritney movement became a world with a #FreedBritney, she can spend her money on little things that make her feel good. For example, candles.

"Lighting my candles sure is a joy folks," she wrote Monday.

As for work and her speaking out about the conservatorship in an interview, it's all TBD. But whenever either of those happens, her legions of fans will be waiting. For now, people just seem to enjoy watching her live her life on her own terms.