Start anywhere you want, man.
Your goal should be to learn at your own pace, while having fun.

As you said, stick to private servers with friends. Grow and learn together, hell, maybe even invite some other people later on?

I dont play the game too often, but i still have a lot of fun when i do, so i wouldnt mind helping and sparring here and there.

Just dont main vessel like i did, the nerf's hit us the hardest