Natasha Jonas has conceded she is in "extra time" in her career as she makes final preparations for her unification fight against Ivana Habazin on Saturday in Liverpool.
The IBF welterweight champion aims to add Habazin's WBC belt to her growing world title collection.
Jonas, who turned 40 in June, has won world titles at two weights and told BBC Sport she has "tried to put a time on" when she would retire "but that didn't work out".
"I'm contracted to two more fights if that's what it is then that's what it is," she added.
Jonas is the oldest world champion from Briton, male or female, and is the second oldest female world champion after IBF flyweight champion Irma Garcia.
But having won all her world titles in the past three years, Jonas is confident she can continue surprising people.
"[There is] satisfaction in myself and not putting barriers or ceilings on what I can do, who I can become and how I can get there," she said.
"I just concentrate on each fight and what is in front of me and then see what presents itself after that but I need to keep winning for that."
A rematch with old rival Katie Taylor remains high on Jonas' wishlist, but her next fight is likely to be a unification fight with Lauren Price should she beat Habazin.
It is the fight Boxxer, Jonas' promoters, have been building towards ever since signing Olympic champion Price in 2022.
Price made history in May when she became Wales' first female world champion in boxing and defends her WBA title for the first time against Bexcy Mateus on Jonas' undercard.
"A loss can close the doors in front of you," Jonas said of a potential fight with Price, who is undefeated in seven bouts.
"For female and British boxing it is a big, massive and momentous occasion.
"We've had Chris Eubank against (Nigel) Benn, (Amir) Khan against (Kell) Brook.
"When you have big domestic rivalries everyone has to pick a side and you have to stay loyal to your team.
"Sometimes we need that as a bit of rejuvenation within the sport in our own country.
"I've got a lot of respect for Lauren but do I think she is better than myself? No."
Jonas will defend her title at home, the third time she has had the chance to fight for world title in front of her fellow Liverpudlians.
Croatia's Habazin has been in the ring with a host of brilliant names including Terri Harper, Claressa Shields and Cecilia Braekhus, although has lost to each of them.
The 35-year-old will be an underdog against Jonas, who says fighting in Liverpool is like "you're Virgil van Dijk and you're playing against AC Milan at Anfield on a European night".
"[Habazin] is experienced, she doesn't come to just make up the numbers. She is coming to fight and to try and take my titles," Jonas added.
"She has got good fundamentals, a good jab and good footwork but everything she does I just believe I'm better.
"I always play it down in my head [fighting in Liverpool], that it's just another fight because you can get bogged down, weighed down in the pressure of performing in front of your friends, your family and your city.
"[But] it's massive. When it gets tough, when it gets hard and you need some inspiration, drive and motivation, the fans bring it for you."