I tell you my experience. I'm leveling a priest that it's 60 now and since I have also done some instances (and I have full heirloom set with 20% experience gain bonuses) and been very ahead of the guide, I skipped some zones since they were grey quest for me, well it was a real mess. Missing quests because I didn't to the previous to enable the following. Going in a zone then realizing that I couldn't do that quest because I didn't do the starting quest chain, very unconmfortable. In short what I suggest you it's not to skip areas, or make really sure that you do all the quests required (at least) and check carefully the previous zone you'll going to skip to make sure that you won't have problems with struggling finding where to start the quest chain to sync with the guide section.
World of Warcraft Gold (US) is a currency used in the US server as a medium of trade. WoW Gold, items are rewarded after killing the enemies. WoW gold is a limited resource and is hard to come by even though gold can be earned by various ways. It is still time intensive for any player to gather the gold needed to get better gears which make advancing easier. Because of the enormous need for WoW Gold, it has attracted many exploiters such as dupers and gold farmers. Arguing that they ruin other people's experience and enjoyment of the game, Blizzard has put up a strong fight to combat these exploiters by banning large number of accounts involved in the activities. However, there are as many players who would not want to invest their time and are willing to pay the extra money to get through the game. Generally, the price of WoW Gold in the EU servers are more expensive than those in the US.
Congratulations on reaching Level 120! There are a myriad of new things to do. The first thing you should do is head to your faction hub ship where you have been doing your mission table quests and footholds to pick up and complete the quests necessary to unlock World Quests. World Quests will provide you an opportunity to grind reputation levels, acquire gear, and gather Azerite. There are tons of new things to do that we will cover in our Level 120 Battle Guide found here: Level 120 Battle Guide