Ride in whatever you've got, you'll soon find what works and what doesn't. It took me years of riding to transition to cycling wear, I'm glad I did, it is better but you don't need to start with it. My suggestions are just that.
Shoes and pedals: stiff shoes are better and a pedal with some grip, little pins are the best will stop your foot slipping in the rain etc...
Padded shorts: Once you've done 20 miles in seamed underpants in the cold you might think about these more. They will not chafe, will provide some comfort for a posterior unused to the rigours of cycling and, especially in winter, will keep your nether regions warm, wet cotton undies will not. You don't want to be doing a ride wondering if your todger will drop off when you finish! I only buy shorts not bib shorts and in winter I just put a pair of running bottoms over the top of them.
Tops: Don't wear cotton t-shirts. Sweat will quickly soak them and they will feel cold and clammy. Man made fibres are best
Waterproof: it's not so much for the rain but for the windchill. Once you're wet a driving headwind, with rain will quickly chill you, a gilet or waterproof will help enormously.
Gloves: definitely help cushion things, will help with hand numbness and grip
Caps/helmets: If you're a glasses wearer consider a helmet with a peak, keeps the worst of the rain off your specs or wear a cycling cap underneath your helmet.
Jackets: Coming into winter a jacket will be necessary. Cycling jackets are generally windproof at the front and breathable at the back. Makes a big difference to a total unbreathable hard shell.
Alternatives and preferences to all of that exist. If you want looser cycle clothing look at mtb clothing, baggy shorts and tops, endura are good.
Even the smallest fly in your eye can be painful. A larger insect can lead to a fairly impressive shiner.
