Sentence:  Instead of going to the unit I walked in the opposite direction towards the medicine lecture room with various thoughts going through my mind — most of them were positive as this was a great opportunity to practise what I had learnt so far and should have a good impact on students who were 3–4 years <WSD>junior</WSD> to me and not known to me. 
Meaning of the word marked with <WSD> tags:  Younger.