1st visit 1955 at age 10
In 1955 my mother inherited her father's car and she brought me and her mother to McDonald Observatory from Lamesa, a long trip at the time.
We were in a '49 or so Dodge, and it vapor locked on the way to observatory. My mother made me and my grandmother get out while she backed the non-running car back down the hill.
My grandmother just stood on the side of the road with her hands over her eyes screaming the whole time, knowing my mother was about to die, but she managed to back down the very narrow road and got the car restarted at the bottom.
I didn't make it to the observatory that time and probably didn't come back until the late 60s to visit, but I'll never forget the first attempt.