Previously held student visa, now applying to language school

I studied abroad in Japan through my US university for one semester in 2013 (a 6 month student visa, “category G”). Now I’m applying to a language school starting this summer, and they’ve told me there might be a problem because of my past visa, but they won’t know for sure until they send my application to immigration. Immigration won’t tell them if my past visa is actually a problem or not, and wants to see the full application first

Does anyone have similar experience or knowledge about applying for a new student visa after already having had one? The only thing I’ve found online is that student visas for language schools have a maximum of 2 years. I did 6 months (at an exchange program, not a language school, so a little different), so I understand if that means I could only do 1.5 years. I’m just really hoping they won’t outright deny me because of one semester 10 years ago