Where's Sophie?

Last night we had kind of a scary moment. I put Sophie to bed around eight o'clock, but shortly before ten Loren heard a noise from her room. He went to check on her but couldn't find her! She wasn't in her crib, so we turned on the light and were frantically looking around her room, in closets and in the other rooms in our apartment. We finally (actually it didn't take that long) found Sophie hiding behind the rocking chair in her room. She was huddled up with her hands over her head, trying desperately not to be seen. When we found her she burst into tears because she knew she was being naughty. Loren thought the whole thing was funny and I guess I do too, but I was really worried for a second when we had trouble finding her! Does this mean it's time to get her a toddler bed or is this evidence that she's totally not ready?