Oh my! You are young op, and sound very together given your age.
Please factor in the exhaustion of having children, it is absolutely ball breaking at times, and although many do sail through this patch with lots of hired help, for the rest of us it is knackering!
Being financially secure is key, if you are going to stop working you have to know you can manage perhaps to very old age. Don't give up on any career unless your plan is bullet proof with at least three plans bs! You never know what is waiting for you further along the line.
Get married so that you are legally protected.
There is no easy road, motherhood is extremely tiring! It is not a holiday and it is easier to be at work in the early days 
My dc are older now, it is a breeze but there are other things waiting - teen years are not exactly effortless either.
On second thoughts get a cat or a horse!!
Have fun planning your life, and I wish you well 