Oh my goodness Lucie, we have been living parallel lives! I am a 43 y/o mum of 3 who has done exactly what you have been doing all these years. My kids knew I smoked, but like you I was so ashamed and embarrassed about smoking that I wouldn't dream of lighting up in front of them. The only person who I smoked in front of was my husband, who still smokes, so my quit was also very solo, the only support I have is right here but you know what? It has been all the support I have needed. 
It's funny, but after six weeks one of my few lingering "triggers" (which are easily ignored now) is when my husband takes the kids out somewhere - that was always the time when I could have a smoke without the risk of being caught. Now, when I have a few minutes to myself, I jump online here and enjoy reading about everyones success stories. 
Congratulations - you come and brag here all you like, you're at a life changing point and have done so well.   
Tess