In my opinion, go for it. For the following reasons:
1. This may be your only chance; could you live with a lifetime of wondering "What would have happened if I had taken that chance?"
2. Not to sound brutal, but its your life, live it. Being a mother is only part (Although obviously a massive part) of what makes you, you. I speak as a Dad to two kids; I love my kids and would die for them, but as parents we have to live our lives too.
3. Shift work allows you to attend more events in the week (Assemblies, sports days etc.) that a job with sensible hours ever would.
4. One of the justifications I have used for shift work is that I am setting my kids the example that going out to work provides the nice things in life. My son used to have difficulties when I left for a night shift when he was younger; my wife explained to him that Daddy was off to work to get money to pay for the eggs (His favourite food at the time) and this helped him; simplistic but it worked for us.
5. Not sure if you have worked shifts before, but I will be honest there are times when it is bloody exhausting. But alternatively, when you have just completed a night shift and you just want your bed, you will find the energy to stand in the rain and watch your son's rugby match / attend your daughters dance medal test / walk them around the park, because we are parents and its what we do.