Is B2/C1 honestly doable ?

So I’ve reached B1 4 years ago when I decided to do my bsc in Germany but that didn’t happen and now 4 years later Im applying for Germany for my msc. I’ve literally forgotten everything about German and I have about 7 months before summer semester starts, Ill do my studies in English but I still want to learn the language. Can I at least reach B2 before going there ?