While I was fortunate enough to be introduced to crypto in December 2013 (through Dogecoin), it wasn't until 2016 that I started to own some due to the urgings of a friend. In 2017 onwards I started to accumulate a bit more, but it wasn't until 2019 that I really got invested in crypto.
My overall investment thesis is that nearly any investment asset is better than the inflationary asset of cash, as all investment assets are measured in cash (USD). Cash inherently loses purchasing power due to inflation, so any asset measured in cash (all of them) will increase over time when denominated in cash. As such, nearly any investment asset is better to hold than cash.
My crypto investment thesis is that crypto as a whole is here to stay. While I can't be certain which of the thousands of cryptos will be leaders in 20 years, I do feel more confident that those which have already proven their worth in both market capitalization and adoption over the past 5 years will continue to dominate in the future.