I'm new, too - not to weight loss and dieting, but to the site. Congrats on landing a job, and on your initial weight loss.
I have three kids, and I know it's pretty hard to balance it all. We're expected to be the best parent, the best employee, make healthy meals from scratch, and get our workouts in! I'm tired just thinking about it. I agree with Sunshine, though, that perhaps intense workouts and completely revamping your diet might be a bit much to start.
I think baby steps are highly motivating - drink more water, eliminate one unhealthy food from your diet, get ten minutes of exercise in. Do one or two of these things for a week, then add another. Soon, they'll just become part of your daily routine.
I think the biggest thing is to not beat yourself up if things don't go exactly as planned. You have four children, and life never goes according to plan with kids. If you don't get a complete workout in, don't let your mind trick you into believing that you might as well eat a candy bar because of it
I think 1700 calories per day sounds reasonable. If you go too low, you'll be hungry. Just make sure your calories are as nutritionally dense as possible. Usually 1-2 pounds per week is a safe bet for losing. Some people initially lose a lot more, then slow down during the process. As you increase your activity and lose some weight, you might have to readjust your calories. You'll figure it out, it might take some trial and error, but you sound like you have a very strong desire to do it! Love who you are right now, too - when you do lose weight, you'll still be the same person