Welcome and I hope that you will find support and encouragement from this forum.
Today is the first day to your better future. Get healthy and fit for your husband, two kids but especially yourself. It's time to seize life and get all it can offer you. No more being the spectator as it dashes past you.
I know from my own experience that if you lose the weight your body will bounce back to fitness and healthiness very quickly. You are tired (apart from the newborn!) because of all that extra weight you are carrying all day long. Once that comes off you'll be bouncing around and full of beans!
It is good that you called it when your BMI showed you at obese. I let it get to super obese before the penny dropped for me.
Start by making small healthy changes in your life. Learn good habits to replace the bad ones. Work at making a healthy lifestyle that works for you and you will achieve success.
Wishing you a better future