Hello! I hope I'm not being rude but I'd like to ask your opinion about deviantart as a platform for a newcomer? I don't have a gallery there and almost no following elsewhere so I was wondering if I should just stick to tumblr and either insta or twitter to start building an audience. Basicaly I'm wondering if DA is a site that's more geared towards people with an established fanbase? thank you for your time! take care!

Honestly?  Do all of them and see what sticks. It can be exhausting to keep up with a bunch of social medias, however they all have vastly different audiences, pros and cons (sometimes the cons outweigh the pros, but its different for everyone).  I know a lot of people who swear by tumblr and never touch twitter, and others who are exclusively on instagram.   Then there are people like me who have a presence on a number of platforms.

DA definitely serves you better if you’ve established yourself on it (though you can say that for any social media platform imo), because there aren’t a lot of people joining up.  It’s mainly comprised of people who already exist on the site and that pool of people is relatively small compared to places like twitter.  That being said its a smaller community and might be easier to get noticed if you’re first starting out. 

Your best bet is to just put your work all over the place, on every platform you have patience for.  The exposure you give yourself the better.