For the most part solid gold doesn't tarnish - and if it does it generally takes a long time generally due to no maintence cleans. It definitely can tarnish (and it's 100% normal) however gold takes much longer to develop tarnish compared to silver. Giving it a wipe down with a soft cloth and keeping it dry/clean helps alot.   More commonly what can happen with gold is something called metallic abrasion where it can discolour your skin.  Again this is completely normal for some people.  It can be caused by a variety of things like chemical interactions (chlorinated water for example) and even biological factors like the salt we excrete in our sweat.  Keeping it clean and dry also helps with this too!