Venus is tracking across the sun today, this evening actually and won't be happening again in our lifetime...unless people find the fountain of youth or extend life so we can live over 109 or so (which may be possible)
Seeing it at 4 years old for the first time and remembering it at 109 when it happens again in the year 2117. And if this person is very lucky and lives to be 117 they can see it again in 2125.
That 4 year old would be extremely lucky to see it 3 times in his/her life.
I also chose 4 years old because most adults only have sporadic memories before that time and those over 4 have a higher chance of remembering it.
Anyways I have to run again