Only been at my job for 5 months, when should i tell?

I'm 24 years old, a network technician at a small-ish firm that specializes in software programming and development for mostly gov't sponsored firms all over the country. I started working for the company in Feb 07 and found out last week that I am now 7 weeks pregnant. Although the company is VERY family oriented (over half of the employees here are related or connected in some way - including the CEO) I am not one of the "related" members of the full-time staff and I'm a little bit worried at how they could react to the news.
I'd like to think that I have a pretty good relationship with the CEO, he's very cordial and interested in our personal lives in a good way for everyone, but I'm not sure that he'll be quite as ecstatic as I am since he is a religious person(although not pushy about it) and I am not married. IDK if it makes a difference or not but any advice would be appreciated to put my mind @ ease. When should I tell them about my pregnancy and how do I go about doing that?

I'm not married but I do have a bf who has expressed his want to become engaged soon and get married - possibly before the birth.

Just tell them when you're ready and comfortable enough to tell them. As far as how they react, they can't fire you or harass you just because you are pregnant, that's against the law.

Being single, engaged or married should make no difference to them, that's a personal matter and has nothing to do with work. As long as you can perform your job, there shouldn't be a problem.

I know your concern though, these days people judge way to fast, talk to whoever your closest to and go from there.
Hopefully they won't give you a problem.
Best of luck and congrads.

Whenever you're ready. Having a baby is happy news, not sad news. Let them share your joy.

Tell them as soon as possible. Look at it this way: withholding this information doesn't change the fact that you aren't yet married, and they will be really mad at the fact that you withheld this information until the very last moment for no real reason. They need to look for a temp to replace you while you're on maternity leave, etc. Giving them very little time to do this is just going to leave a sour taste in their mouth just before you are going to be gone for 3 months. That's not the way to leave things if you want to stay there.