Assembly wasn't to difficult. My 3.5 year old son loves it, after cosleeping with us since he was a baby, he was ready to sleep on his own and stay in his own bed because he loves this bed so much. We used his twin mattress and it fit perfectly. I only gave it 4 stars instead of 5 because we found some scratches around the car, and we found the stickers were a bit difficult to stick flat onto the car.