Based on what little I know of Japanese, the first syllable isn’t supposed to rhyme with ‘Rick’, but should rhyme with ‘weak’.
Most eastern languages are very particular about vowel sounds which is what might be throwing Siri off. I think English probably stands out among other languages for playing fast and loose with how vowels are pronounced. Results in some unique challenges for sure.
My gut had me wanting to say the same thing, but looking at the age ranges, this actually seems reasonable and in line with how many other countries operate. By 6 years old, students in the US are in first grade, for example. Kindergarten a year or two prior as well, which is also compulsory in some states.