Is she health tested? I'm not very familiar with Labs, but I know they definitely need to be hip/elbow scored and eye tested, there are also DNA health tests available for Progressive Retinal Atrophy (causes blindness) , Exercise Induced Collapse and a few others. 'Book of the Bitch' is some good reading material.
Do you know her lines well, and are her original breeders happy for you to breed from her? Many puppies that are homed as pets have a breeding/export embargo placed on them - important to check that your dog does not have this as the Kennel Club will not register any puppies from her. Will you have a waiting list, and will you screen potential new homes extensively? Will you offer a first refusal contract to all of your buyers - that if at any point in their pups life they are unable to care for it, you will take it back so that it doesn't get passed to a rescue? Will you yourself place breeding endorsements on the puppies?
Honestly, if you have any doubts about breeding, I just wouldn't go for it. Perhaps not what you want to hear but people need to be 100% certain and know what to expect. Maybe it would be worth chatting to her breeder and asking if they would mentor you if you're really keen?
Would you be willing to travel to find the perfect stud dog and pay stud fees? She is a maiden bitch - there's a very good chance they may have trouble actually mating - would you be willing to assist them if needed? It's not pleasant! You may need to monitor her cycle. There is only a very small window during a bitch's heat where she is most fertile and actively receptive towards the male's advances - if you try to mate her too early or late she may not stand for him, and some bitches can even become aggressive towards the male. Some people use blood tests to determine whether their bitch is in this most fertile point - another added cost.
Will you buy her a proper whelping pen? It should have pig-rails so that the mother doesn't accidentally sit on her puppies.
Could you afford an emergency c-section if your girl was to have trouble giving birth?
And this is all before she has given birth! Once she's had her litter (keep in mind Labs can have very large litters) you will need to monitor both mum and the babies. Daily weigh-ins for all the pups to ensure they're putting weight on properly. Making sure that the pups are feeding properly - lactating mothers can be prone to mastitis, a bacterial infection that can be fatal if left untreated. If a pup was failing to thrive or the mother had rejected it, would you be up at all hours of the night to bottlefeed it? Would you be able to be at home to regularly watch the pups within their first 1-2 weeks of life where they are most vulnerable - I have seen very sad situations where the breeder left their bitch and litter alone for just a few moments, came back to find a dead pup that had unfortunately been accidentally sat on by the mother and suffocated. You may need to take time off work to watch over them through those first vital weeks.
Prepare for loads of washing - puppies will pee and poo all over their bedding, and themselves! It is very hard work. Once they open their eyes and start walking, that's when things start getting interesting. You'll need to keep them busy with toys, regular handling and socialisation/exposure to family life so that they have those foundations there to build on when they go to their new homes. Pups will need to be microchipped by law, starter vaccinations, weaning onto solid food.. more costs!
Honestly, it's all very expensive to raise a litter (if you're doing it properly!) and many good breeders are lucky to make even when they sell the pups. It can be very rewarding to produce quality pups and see them grow up and the joy they bring to their new families. But it is a LOT of work, blood, sweat and tears. I have seen the sadness when things go wrong - there are a lot of things that can go wrong and can't be foreseen. I've seen people lose their dam during the birth, stillborn pups, accidents resulting in the deaths of pups, fading puppy syndrome, pups born with birth defects.. it's never straightforward. Even the most experienced breeders can have these things happen and it's heartbreaking. Some bitches may not even become pregnant from the mating, or carry the pregnancy to full term, just like with people.
I'm sure I've missed some things out, but ultimately if you're really on the fence about it, I'd say no. A lot of people think it would be lovely to have a litter off their family pet, but there are a lot of risks involved. Not to scare you but you need to be aware of what can happen, worst case scenarios.