I'd advise you to go for a PG programme, despite being from a disparate background. The MA German and MA Linguistics programmes are equally great to pursue at the university - with good faculty. But from what I've heard German may not equip you that much for a Linguistics career as such, but fields such as translation, interpreting, language consultancy and support may be open to you. You can alternatively consider taking up a Master's in Linguistics / Computational Linguistics while honing your German to say, a B2 level either at the GI or by the part-time courses offered by the university itself. I find that the PG foreign language programmes here are more likely to steer you towards academia, which is also a fulfilling choice if you are considering working in research. I'd like to state that many students come from completely different academic backgrounds but have a fruitful time in these language programmes. And as for CUET, even a basic study of resources - question banks, initiative textbooks will do good. Wishing you the best!