When to send out baby shower invitations??

I haven't had a baby in 10 years and I feel like a FTM and my friends kids are all older than mine. 
I read to send out the invitations 6-8 weeks early but that seems like too much time. Is that the correct time frame??
When are you ladies sending out the invitations?
Also, I'm doing custom invitations for family, mainly because they are older, and evites for my friends.