I picked up Go this Christmas. I’m 50+
My motivation was to be able to play with my teenage children, who started at that time.
It’s taken me these 4 months, playing a couple of games a week, to get to 20k.
There are some big help things that I found:
- InSente’s beginner go series
These were definitely best “getting started” thing I found.
Note, though, that this series takes you only so far: really beginner stuff. It’s great for that. It changed me from always losing to my son, to being able to beat him for a while.
InSente’s other material is good, but not “the best”. “The Best” I found are:
- Dwyrin and Nick Sibicky video lectures. Especially Dwyrin “basic shapes” series
These are pitched at “DDKs” as if that term means “beginners”. But an 11k person is a DDK. An 11k person is a guru compared to me and you. Me and you are really “TPKs” … twenty plus Kyus … and we need much more basic help, like InSente’s 
But after InSente’s, you do need “the next level” which Dwyrin and Nick supply. So you have to pick the material and just not get lost in the advanced stuff.
What worked for me:
- Learn the rules on 9x9. I found I was quickly impatient with this, so I quickly went on to…
- … try 19x19 for the feel of it. You can have some fun games stumbling around, until you realise you have no idea about life and death (tsumego)
- Go back to 9x9 with a goal of getting excellent at tsumego.
- When you can count liberties and fight, go back to 19x19
- Find out what “corners side centre” means, and what “big moves” means, and do those
- Look for “basic beginner joseki” videos, to give you some grounding in how to respond in openings
… but don’t get to hung up on memorising. Just be aware that they exist and the most basic ones you can expect.
… Sensei’s library has good coverage of these too: eg 4-4 point low approach at Sensei's Library… from this page, you’d only really need the first one to start with (low extension) - Same with fuseki (standard openings). The only reason for a “TPK” to know one or two of these is to have some clue what the opponent is doing, but don’t get hung up on them. I read somewhere that “The first 10 moves of Kyu games don’t even matter”. Obviously that is an exaggeration, but maybe it illustrates the point.
That gets you to 20k