I was also brought up during the metric conversion, but unlike the others it didn't leave me bilingual, just confused.
I have dyscalculia and estimating weights/ heights/ distances is tricky for me anyway, unless it's by direct experience. So I know how far 60 miles is, because I've travelled that far, I can feel it. Recently tv programmes have started presenting distances/ speeds in kilometres and it drives me crazy because by the time I work it out, I'm way behind in whatever I'm watching. I understand that they're trying to move us totally to metric, but while cars and signposts are still in miles it's not really going to work.
Same with weight - I was watching a programme on elephants seals last night. Yes I could see the males were big - bigger than the females, but on a rocky shore there isn't much to put them in perspective. No use me trying to remember how many kg they said they were, it was in the hundreds and that's all my mind retained.
I can't think in kg, km or cm (for height) until it becomes the standard and I have things to compare it to
(Degrees celcius is natural for me because I never learned to judge temperature by farenheit - ironically i have to translate it in most conversation)