Welcome. There are so many patterns for various situations. By all means soak up all the good advice.
Personally, I wouldn't worry too much about flies. Remember Tenkara style fly fishing only uses about 4 patterns with great success. Think positively and focus on presentation and patience.
I think if you focus on a few themes. For instance Color is a good place to start. Be sure to have patterns throughout the color spectrum or at least the lights to darks, earth tones and bright flashy. Get a few patterns in dries, wets, brass head nymphs, and streamers. Be sure to ask for advice at local shops or anywhere you come in contact with fishermen or women.
Also I really find smaller rivers or large streams with deep holes, to be rewarding and fun. The fish are smaller but may be more forgiving to your patterns and presentations. Sometimes the bigger deeper waters with limited visibility can be frustrating and hot and cold.