can you take care of it properly until it grows up? do you have the funds? the attention to give it and your other two kids? do you want a 3rd kid? are you a good mom? if yes to ALL, ALL of these questions, and you're SURE then yeah go ahead have a kid
If love childern and can take a good care of them then there is no problem in have a third child it's our duty after all to leave Successors to longevity the earth
if you allow your finances you can