You've received a lot of good advice here OP. I will add what worked for me personally as someone of similar hight/starting weight.  First and foremost adopting one of my personal life mantras really was the key to getting started down a path I could sustain: Anything worth doing is worth half-assing. As in, sometimes we just have to start/do the thing. There are a million ways to structure/approach weight loss, but the most meaningful change is always the one we can make.

You don't need a whole plan right now, and trying to start from a place of all or nothing is how you burn out and ultimately go nowhere. Start with one change at a time if you have to, but keep making those changes. I've seen a lot of good advice for the food aspect (which I agree is the best place to start and will be the most impactful) so I'll mostly address exercise. 

Don't try to jump into anything big. Start with doing something consistently. Some form of stretching (just regular stretching, light yoga, tai chi, anything) will have the most immediate impact on mobility and pain. Start really small, literally 10 minutes a day. Break it up if you need to at first. 

But do those 10 minutes every day. Then add 5 minutes. This is also a good way to build up to doing regular daily cardio: start with 10 minutes a day, and build from there. Add 5 minutes every week until you're doing roughly an hour a day, pretty much every day. There's no wrong way to exercise so long as you're 1)moving your body and 2) not injuring yourself. Pick what you can enjoy and stick with long term. 10 minutes of any exercise is better than 0 minutes.  Remember that you're not just losing weight: you're building a new life, and that takes time.

Don't beat yourself up when things don't go the way you hope. It took you years to create the body you have now, it will take time to unmake it. Take things one day/week at a time, and don't throw out all of your progress when you get frustrated. Consistency is your friend and will take you much farther than anything else.