2 year old + painting a room = frustration for all

I have this horrible fear that this baby isn't going to wait until it's due date and nothing will be ready in time. So therefore I have gone into near panic mode, I need to have everything ready and set for when the time comes. Unfortunately, limited finances have made this a slow process. The only really big thing I need is a crib, but really, I do have a cradle that the baby can sleep in until I get one. So it's not like the baby won't have somewhere to sleep. It just feels like a nursery isn't complete without a crib.
About the painting though. We are painting two walls across from each other green with ivory stripes and the other two walls will simply be ivory.Attempting to paint with Seth around is a horrid nightmare!! He wants to " help" paint, but he wants to paint ivory on the green walls and vice versa and himself in the process *sigh* And if just one of us is in the room with it locked he fusses and fusses to get in. And even trying to organize the baby things with him around is difficult. He keeps insisting " open it" or " have it".
He hasn't been listening to us lately and has been extra crabby. I am wondering if he is more aware of this whole new baby thing than we know. Maybe he is already starting to get upset with the whole idea of having competition for Mom and Dad's attention. Sometimes he seems to be far more observant that we give him credit for so I wouldn't be so surprised. Poor little guy. He won't be my only little boy anymore.
David isn't very motivated at all. He has a hard time understanding that my due date is March 2. He claims that since this child was conceived June 9 that the due date should be March 9 instead. I tried to explain that it is calculated in weeks , 40 to be exact, which is really 10 months of pregnancy and that includes two weeks BEFORE conception because pregnancy is dated by last menstrual period.
That just confused him more.