Back in the days students usually start with secured credit cards (very low CL), or entry level such as Discover/Chase Freedom, same for Citi (Citi Dividend/Forward and an even older version rewarded for maintaining certain GPA...). It would have been possible to start with some easier ones, such as Citi Preferred, then wait for a few months for AAdvantage. If you are applying for internships domestically you will eventually obtain SSN.
However now it's indeed next to impossible due to current situations.