Anecdotal, but I know way more people truly bilingual people in the US who learned Spanish at home and then English later than people who learned English at hom

Anecdotal, but I know way more people truly bilingual people in the US who learned Spanish at home and then English later than people who learned English at home and then Spanish later. The latter is extremely rare and takes years of study. The former frequently happens almost by accident (not to discount the difficulty of it).