Why does my 19 mth old daughter act up as soon as another toddler is around?

For instance, we went out to dinner with friends last night. They have a one year old little boy and he sat across the table from my daughter. As soon as my daughter saw him, she began to fuss and was trying to squirm out of her chair. Then anytime he would try to say anything whether it be babbling or yelling or whatever - my daughter starts freaking out even more. Does this sound like jealousy, like she didn't like having to compete to be the center of attention or something? She will act like this a lot when other little kids are around. Is this normal?