Just because Grandma's story sounds "off," don't conclude it is wrong. My grandmother told me that she could remember getting baptized with her younger sister. I never argued with her about it, but I doubted it--Lutherans were baptized as babies.
Sure enough, for some reason (not the lack of a minister in case someone suggests it), Grandma was baptized at the age 5 or so, with her sister and baby brother. Turns out she was right after all.
However, she was wrong about her brother's middle name, but that's another story--and another tip.