If you wanna study rigourous mathematics. Then I'd suggest do not follow engineering mathematics book. Instead follow some theoretical one, but it will take longer time.
You can still use the real analysis book. It's undergraduate and doesn't require prerequisite. But it will be slightly hard to read at this level. But if you get used to reading such statements at this point of time. You will be able to do really well
Even the basic chapters would do, as long as you practice 'reading' mathematics