Reassure or dissuade me

We’ve put the deposit down on a female lab puppy and I’m getting nervous reading all the posts. For context, we have 40 acres (80 combined with family next door). We have 3 small children (5, 3, 1) and plan to have more kids. A dog seems necessary to us to help with deer/coyotes/snakes – it’s partially a safety issue. We also know our kids will love a dog. We lost our last dog in an accident and our oldest still talks about him 2 years later. We live about 30 minutes out of the closest town, which means when we need to go into town it’s NEVER less than 2 hours. Usually around 4 hours. I’ve been doing a ton of reading on training and feel confident in my knowledge of what it takes – I’m just nervous it’s actually really unrealistic for me to spend so much time with a puppy while I have 3 small children who also need my supervision. I’m very hesitant to adopt an older dog because of our children and other animals – as well as not wanting to have to undo poor training. Hype me up or tear me down!