Derenda, so glad to year you can experience a little bit of Disney at Downtown Disney and
DisneyQuest. Your 12 year old daughter will really enjoy all the interactive and unique fun that DisneyQuest has to offer.
Unfortunately, strollers are not permitted in the building. There is a designated stroller parking area outside the building. Keep in mind that inside it can become very loud with all the music and crowds and the flashing lights might overstimulate your youngest daughter.
In regards to you being pregnant, you will want to check the warning signs on several of the rides. Often for your safety and the safety of your unborn child, it is strongly recommended that you do not ride certain rides or take caution. Disney take the safety of its guests very seriously!
If you feel that your youngest may not enjoy it and that you may not be able to ride some of the rides, you may want to sit this one out and enjoy walking around Downtown Disney while your husband and older daughter enjoy the games and attractions inside. I wouldn't want you to feel that you are spending money on admission to a place that you can't fully experience. However, this is just a suggestion.
Have a blast at DisneyQuest!
~Allison L