15 month old does not like being touched by strangers.

My baby will be 15 months old soon, and all of a sudden I’ve noticed a shift in his social behavior. He waves and smiles at people from a distance, but he doesn’t like it when they come too close or try to touch him.

We’ve been on a couple of vacations with him, and on the flights he was smiling, waving, and trying to play with people. Recently, one of my friends visited our house and tried to pick him up. He was running around happily and smiling, but he gently pushed her hand away. Another time, a 2.5-year-old child came up to give him a high five, but he looked at the child for a few seconds and then turned his face away. He seems to get a little scared in those situations.

I’m looking to hear from parents who’ve had similar experiences. Is this just a typical stranger anxiety phase, or is it something I should keep an eye on? Otherwise, he’s very social and affectionate with close family members.