Pregnant cat won't stay inside

My pregnant cat gets out every chance she gets. Like right now my 2 yr old let her slip out and she's been outside for six hours in the soaking rain! Is this normal? If so is it any indication as to how far along she is? She's pinking, and showing but I can't feel the kittens (not rly sure what to be feeling though) and I see no fetal movement just yet. I know she's anywhere from 4-9 wks but other then that I dunno.

Has she always been an indoor/outdoor cat? If so, it's likely that she just enjoys being outside and wants her time to prowl around. Wanting to go out is not really connected to any "phase" of pregnancy, but it could be an indication that she's getting close and wants to go searching for a good nesting spot. 

Trust me, when the kittens start moving you will know it. And, as a general rule once they start moving around you are about two weeks away from delivery. SInce you aren't feeling them you probably still have a few weeks to go. 

That said, she needs to be brought indoors now and needs to stay there until after she is spayed. If she continues to go out you are going to have a tough time with her.  If you wait to bring her in until she's almost due she's going to be very unsettled and that can lead to problems with delivery and kitten rearing. Also, since you don't know exactly when she is due you her having the kittens outdoors where you can't find them. Finally, being outdoors she is exposed to tons of germs, fleas, and parasites. You want to get her to a vet to make sure she is healthy and dewormed before the kittens come. That would all be for nothing if she just went back out and re-contaminated herself. 

I know you said your two year old let her out but for her wellbeing and the safety of the kittens this just can't happen from this point on.  Your best bet is to confine her to just one room (a spare room or even your bedroom if you have to). This way she has a lot more hurdles to get through before she can make it outside. And, setting her up in there now with a birthing box and everything else she needs will give her time to get used to her new limited surroundings and allow you to block off the places that you don't want her to go for delivery (such as under a bed). It will also be a huge benefit once the kittens come as it's way less area that you have to kitten proof. 

Cats can go back into heat quickly after giving birth (as early as 4 days after) and if allowed outside she WILL get pregnant again long before this litter is even weaned. You are looking at her being indoors only for at least the next 12 weeks so really put some time and effort into making her comfortable with being confined to one room. Until she is spayed she absolutely must stay indoors- no exceptions.