What's a good exercise plan for me)?

Running, cycling ect will help you loose weight. Weight training will also help- don't turn your nose up to it strength away. By building your muscles you don't just help take the strain off your joints but y having more muscle, you use more energy without realising it but don't rely on this "without realising it" because nothing will ever happen if you don't do anything at all. Biggest thing I would suggest is diet. Reduce the amount you eat but don't starve yourself otherwise you won't loose any weight either (that's another long story) when you do exercise make sure you try your absolute hardest. Ignore any negative comments anyone has to say about you, just picture your goal and go for it and believe in yourself, your goal is 180lb, although reaching this target would be amazing for you, try aiming for 170,160,150 as you reach each target. Again don't say no, don't be scared of failuar to try and attempt these goals either, if you don't ignore the fear of failure then you will never try and never succeed.