This question comes up a lot and it all depends on the person. It comes down to which your native language is, previous experience with language learning, and motivation. Some people need a few months, some people years to because conversational in a language.
If you want to support the project once, you could get something from the shop or just share Say it in Swedish with your friends and foes.
Yes, of course!
This site is made to give you as many tools as possible to learn Swedish on your own. Say It In Swedish doesn’t offer private lessons with a teacher however you can join the free Discord community to practice and ask questions.
If you want to connect your accounts to get all the extra goodies, you can do that in your account settings. There is a connect button there for Patreon.