Mines is November 8th and I plan to give my invitations this week that people can plan ahead and time and able to make it and to get their gifts also.
I would give them out now and remind people threw text message a week before
We did about two months, but I have a lot of family living all around the country and we both have nurses in our families working in different hospitals. They make their schedules months in advance. I would say two weeks to a month is normal. Most people can work with schedules within that time frame.
Its not to early, thats 4 weeks away and typically when people give them out. I gave mine out 2 weeks ago and my shower is next saturday.
I would give them out now that way ppl have time to prepare.. like buy a gift and maybe take off work :)