My LO used to do that when she is 3 months old. She just loves to stand. I didn't let her stand for a long time. Until now she is 6 months old, she still loves to stand with adult hands support 🤷🏻♀️
Her legs are very strong and straight when she is standing, especially when she is in the car, she tends to stand up so she can see outside 😂
Thulile Theophen Hlongwane