If you're looking to apply to medical school next year, 2023, then you'll be beginning medical school in July of 2024. If you meant that you would like to apply this year, 2022, then you will need to accelerate what I'm saying below by one year.
Most would agree it's advantageous to submit a completed app on the first possible day of the application season. While you can submit your application without an MCAT score, it's best to plan on having your MCAT result to make things less complicated. The AAMC does not provide for us the MCAT score release dates for those who wish to matriculate in 2024, as you have indicated, however we can use their
timetable for the 2023 matriculation. Cross reference this with the fact that your MD application can be submitted the
first week in June, and you should be taking your MCAT no later than April 30. Again, this is using the MCAT timetable for testing this year and matriculating next year. You've indicated you'd like to matriculate in 2024.
I would add two things. First, you don't know if you'll end up needing to retake the MCAT. No one plans on this, however you should strongly consider taking the MCAT earlier than April just in case you end up disappointed in your score.
Second, you indicated you are only interested in applying MD. I would recommend planning on applying DO as well, unless you're 150% positive you would never attend a DO school. If you change your mind and plan to also apply to DO schools, know that the DO application (AACOMAS) is completely separate from the MD application (AMCAS). Further, the DO application can be submitted
the first week in May, which is about 30 days earlier than for MD schools. With this being the case, I'd plan on taking the MCAT no later than March 25 if you know you won't possibly retake it. To be safe for a retake, I'd suggest taking it early January.
As for MCAT prep, there are endless ways to do it.
Option 1, 6+ months of part-time preparation. If you're remaining fully employed, this is likely what will work with such other commitments.
Option 2, which is arguably the most common: ~3 months of full-time studying. This will mean you quit your job and study 40+ hrs/wk for at least three months.
Option 3, which I would personally do if I could go back in time: Pay the money and do an expensive review course with a well known test prep company. Anyone can score 510+ with a proper study plan, but these companies actually offer a money back guarantee if you follow their program. I believe you can even get on a weekend-only schedule and maintain your full-time job. The beauty of these review courses is that they are complete and force you through years worth of material in a very regimented schedule. 2-3k may sound like a lot, but it really isn't considering how expensive a single medical school application cycle can be.
Best of luck!