The same as Fi - I have a friend who's little one was rolling/crawling before Jacob and would get into things, but boy have the times changed! She is now very quiet and reserved and doesn't really talk at all, and takes a little while to adjust to play sessions with Jacob, who was the first one walking and is now into everything and generally quite out going. He too can have his quiet and reserved times, but for the most part, he's very outgoing compared to his little friend now.

Honestly I don't think there's any problem - if anything, showing a little caution is a good thing at the end of the day!