Anniina Korkiakangas I like the drive! I want to tweak one thing about what you stated though: It's good to have a stack/technologies in mind and it's fine to start out with the exact ones you said... However, please do not "marry the stack." A construction worker would never say "I'm looking for a job where I can use crescent wrenches, a Sawzall, and a shovel." Likewise, you shouldn't limit yourself either to TOOLS.
What I mean by this is that, if you become proficient with all of those techs, you may find a job where you use your Postgre and Django skills, but where they don't want Swift/iOS.. Or you may find a Swift/iOS job that doesn't require Django or PostgreSQL or uses React Native instead... If you become good with the stack you stated, you shouldn't limit your professional opportunities to the stack because good companies will know that someone who is smart in x y z stack will also be smart in a b c stack after he/she learns it.
Shit, you may even find a C++ or Objective-C (deeper than Swift but still Mac) job where you met a really nice person who likes you and thinks you'd be a good fit if you're willing to learn C++ or Objective-C. You never know.
So, again, it's great to have a specific stack in mind and go ahead and learn it, but just don't let it limit you if you cannot find an exact job match, apply for others anyway and network.
As far as mentors go, IN REAL LIFE is the way to go if you can. Find local Postre, iOS/Swift, Python, Django, etc meetups... That's a lot of keywords to look for on meetup.com so give it a shot. Also, try Facebook groups and if you can't find any, make your searches mor general "web developer meetup" etc...