Try to in 30

I really want my #3 child. Its be a struggle with this pcos. I don't know when to stop trying. I have 2 girls one 8 & 1 about be 7 next month. I don't want them be to old for a sibling. I'm getting concern since someone to told me I'm get to age where ur baby has a great change of down syndrome. I need advice. I really want a baby boy. I need all the comments I can get. My glow I'm past due but I'm not regular so I don't wanna test and see a negative. Help, help help. I'm will be 33 next month.