You're right to be anxious. Not because it's awful, but because taking on a puppy is a huge commitment. We've had Jasper for 5 months now, utterly adore him, but it has been hard work. The first 6 weeks were really tough, and I questioned myself several times a day as to whether I'd done the right thing. In fact, in all honesty, I still have moments when I go 'Oh shit. This is for the next 15 years. The poo, the hair, the mud, the walking...'. That said, I wouldn't be without him now. He is very much part of our family, and the DC adore him. But make no mistake, if you're at home, you'll do the majority of the work. Puppies are like toddlers that never grow up, imo. Expect to feel completely overwhelmed initially. Expect to have a heart sinking moment when the pup 'bites' someone enough to draw blood, or destroys something precious. Expect to panic when you walk in to a room and 'smell' the dog. Expect the puppy to exhibit behaviour that will make you consider emigrating, at least once. The situations you are prepared for will never occur, the pup will find a whole new way of changing the rules. Expect to fall hopelessly and completely in love with the little sod just when you think you can't cope any more. Be totally realistic about the dog's behaviour, he will come untrained and without manners. In the same vein, don't be pissed off when the puppy misbehaves horrendously if you haven't trained him how to behave in certain situations (ongoing, this). Expect to make dog walking friends, and have at least one iffy run in with a dog walker (there are a lot of irresponsible owners about who are quick to blame a novice for their own shortcoming. At least, that's been my experience).
Reading this back, it looks like a list of negatives and a bit patronising. Sorry, that wasn't my intention. I'm certainly not an expert and am learning on the job, so to speak. Think of this like those lists of horrendous things people say about newborn babies that make you want to run for the hills. Yet we all know that there are positives to babies, and the same for puppies. If you put in the work, get to know your new addition and spend time training him, he'll be your best friend :)