Good to see another guy on here
Your current weight for height is probably ok. Ideally a guy of your height should be between 68 and 85 kg. So 75 seems ok and you would not want to get below 68, that would be getting in an unhealthy weight range.
Remeber, muscle weighs more than fat so 68 - 75 is also only a guide, a lot also depends on your body make up, muscle v fat. Therefore, could I suggest that you have someone check your percentage of body fat, it may be that this is ok, or it may be they recommend you loose some body fat. In which case you can get a more accurate picture of how much to loose, safely.
I work with young men around your age who are involved in sports, particularly rowing. And I know how obsessed they and their team mates become with weight. I hear many conversations from people, for example, hasseling the stroke because he is too 'fat' when there is nothing of him already and they work out in the gym far too hard to loose what little protective body fat they have.
Your BMI is currently 22 and should be between 20 and 25. I think its good you are conscious of whether or not you need to loose weight, but take some friendly advice and find out just how much you might need to loose, given that you are almost in the middle of your weight - height ideal range.
Since you have decreased your sporting you should also become conscious of how much food you used to need to compensate for the amount of exercise you were doing and how much food you need for your current activity level, this well help you to stop putting on weight as typically happens once young people leave school, or stop sports, who have previously been very active.
Some of the young lads I deal with eat in 1/2 a breakfast what I eat in a week but they train like the bejezus and the moment they stop training but keep eating the same they will balloon up like nothing else.
So take time now just to learn about your body, how much you need to eat v how active you are and get into a life long habbit so you don't make the mistake people like me have made and wake up one day and find yourself overweight.
Best of luck bro