Should I get married before or after citizenship?

[Itanium]

Hello,
I'm a Green Card holder (6 years), and I'm going to apply for citizenship very soon.

My fiance came to the US with a tourist visa around 2 years ago. (so she's here illegaly now..)
We want to get married, but I would like to know what would be better for her?
Should I get married before applying for citizenship or after I become a US Citizen?

Also, I'm not sure if this matters or not, but we have a 2-month old son (US Citizen).
Thanks a lot!

 

[cafeconleche]

After!

 

[Risah]

After will definitely make things easier.