I have a story very similar to yours...very active in 35mm and 4x5 B&W photography in the 70's ('souped' my own negatives in my own dark room setup) but then, went to sleep on photography for a lot of reasons until 2014. I felt like Rip Van Winkle waking up after a many year sleep only to find that 'digital had happened'.

I started w/ a Nikon D750 and read a few things I could find about digital basics but I found that the single thing that helped me the most was John Greengo's 'Fundamentals of Photography' at www.creativelive.com. It cost a bit of money but the content is comprehensive and the graphical way of presenting it that John has developed makes learning interesting and entertaining. I REALLY commend that course for your consideration.

I have learned also that some way of cataloging your growing collection of digital photos so that you can find any one by certain criteria is a necessity. After a good deal of research, I settled on LightRoom. The 'post' photography 'work-flow' is a whole new and entertaining aspect of the digital photography world today.

One last hint that I gleaned from two different presenters at a local photo expo last Fall was that not NEARLY all of your photos are worth keeping much less spending time in 'post' to key word and tweak. Culling is a necessary part of the post photography process and the similar remark by two of the presenters that 'I only keep about 10% of what I shoot' took away a lot of the guilt I first experienced as I did my initial culling sessions.