Other answers are very much on point, but I want to flag a point others are not focused on.
While I’m currently living with my parents and paying $700 per month in rent, I’ve been thinking seriously about saving more aggressively now that I’m just starting my career.
You should absolutely be doing this, and it should be a focus. I don’t think it’s a reason not to donate, but this has been discussed several times before.
And on donating now vs. later,
https://forum.effectivealtruism.org/posts/7uJcBNZhinomKtH9p/giving-now-vs-later-a-summary
By what authority does such ownership exist? Because at some point, we’re arguing over which social structures (ownership, government, negative rights) are good or bad, and I don’t see much justification to draw the line where you choose to.