Hey man (I'm assuming)! Welcome to the community, and congrats on deciding to shoot for FI so early in life; I'm sure by now you know all about the magic of compound interest and why that's so important.

However, your plan seems to me to be what I might call "ridiculously optimistic". Perhaps "aggressive" is a better term, seeing as how shooting for FI in only 7 working years is a dream I think even most of the people on this sub would consider fast.

My first issue with your plan is that you intend to live, for hopefully 50-80+ years, on $18k/year. Where do you intend to live? Do you ever plan on getting married, or having kids, or taking a vacation? That seems like a very, very low amount to set your sights on. Do you think maybe a few extra years of work (that you hopefully don't hate, because with your skillset why take a job you hate?) might be worth living more comfortably for the remaining 40-70? I dunno, I don't buy into the frugal living thing as much as some others in this sub, what do I know.

Next, and perhaps more importantly, is that I see very little margin for error in your plan. 10% (and that's after inflation, right?) is a pretty aggressive growth number. Do you know what housing is like in your area? Do you have a written out timeline for acquiring 15 units? What happens if you ever have a serious setback, like a health issue or another housing downturn? Does your plan allow for this? MMM has a great article on safety margins--taken from his engineering background, no less--that I highly recommend you read.

Overall, I think you're absolutely setting yourself on the right path by getting a good, employable education and by making yourself financially aware early on. I would just caution you not to shoot for the most aggressive possible path without a safety net to catch you if you falter. You've got a long life ahead of you, make sure you enjoy it!