I honestly think she'll be fine going back to Berlin. People of age 33 can book their appointment for their first vaccine atm
Since the new academic year will start in the end of August/September, she'll probably be vaccinated by then (even if the vaccination program gets a slight delay).
If she's fully vaccinated, I think Germany will allow her to enter the country without any big problems. And even if Jade has to quarantine, she'll probably be willing to do that just like entering South-Korea
(
https://www.bbc.com/news/uk-57209444)
I mean this is just my estimation based off what I read in the news and the progress of the vaccination program in my own country (European)