I agree with Banjoest. I have a good friend who had been a performing amateur multi-instrumentalist for many years but waited until he was over 40 before he committed himself to reading music. His wife sat him down and taught him the basic concepts in an afternoon. It took much longer to become fluent, but he did it. He can now play squeezebox and mandolin much better as a result.

Ear training should be part of the learning process, and that too can be accomplished as an adult.

Find a good teacher of your musical interest.

As for tab, I find it infinitely quicker to write, so much so that it is how I generally shorthand music. I include the usual standard notation timing and key indicators either on the tab or on the 5 line staff above. For things which are of a more permanent nature, I write it all out abc style.

In the end however, reading and writing doesn't complete the necessary skills these days. Improvisation, (including embellishment & interpretation) rely more on ears than eyes and pencil. The important thing to remember is that each element of this equation is mutually supportive. In other words, as your ear improves, so your improv improves, and so your reading/writing improves, assuming you pracice all three.

Peace, Mooh.