you are in the best position to decide if you are ready for the exam in realistic terms.
because you went out of your way to make a thread asking other candidates, i can only assume that you are not looking for a motivation “you can do it” post, but rather honest opinions from other candidates who are also under the same situation, or have gone through a similar situation where they dont think they have the time to master the material, yet waiting for the next sitting is not an attractive option, either.
if you decide to take the exam in 2020, you are more likely to spend your limited time more effectively. you may be surprised by how much you can get things done by simply using your time more effectively. being on a tight time constraint help against procrastination. even if you don’t pass the exam, you are likely to learn a great deal in the process, and thus have a better chance at passing the exam in your second attempt. the cfa institute revises the syllabus yearly, so that some of the reading for the 2020 exam may no longer be relevant for the exam in 2021. however, the core material should be mostly similar. taking the exam early means you will have to pay a fee of $1k (for an exam you dont feel completely prepared for and is not exactly cheap), and you have significantly less time to do everything else.
if you decide to postpone the exam, you will have more time to study and master the material, but this also makes you more likely to procrastinate. there is also a time decay factor, which should not be underestimated. people naturally forget what they have learned as time passes (even CFA charterholders forget, particularly concepts they rarely, if ever, use in their daily jobs). in math, they call it the “forgetting curve”. even if you learn the material after 6-7 months, there is a risk that you will forget some of the concepts by the time you take the exam. you will need to make an extra effort to offset the effect of time decay.