There is no official launch date for the laptop version of the RTX 20 series . However, from what I recall they mobile versions usually lags behind by at least 3 months so you are looking at a possible January 2019 for the initial release to select brand names (most likely Asus, Dell and Lenovo) and it will likely be another 2 or 3 months for a wider release so that other brand names will get them.
As for whether or not it is worth waiting for the RTX 20 series to be released... I suggest you Google for some RTX 2070 / RTX 2080 reviews and look at the benchmarks for both games and photoshop. I have seen headlines that stated the RTX 20 is provides 50% better performance than it's GTX 10 counterpart. But that is only the headlines and many times they are a bit sensationalized to get people to click and read the article.
Personally, I can wait. One of my laptops is an aging Dell Latitude 3540 from early 2014 with an i5-4200u and Radeon HD 8850m (basically equal to a 940m with DDR5 RAM). It still works, but I would like to replace it with a laptop that has Intel's 10 generation 10mm Cannon Lake CPU that is expected to be released sometime in 2019 after yet another delay... A RTX 2050 Ti should good enough for my needs. But if a laptop with a RTX 2060 is not too expensive, then....