There is no formula of work experience that will get you to an MBA. Everyone has their own path based on type of role, responsibilities given or seeking, industry, the economy, etc.
For the most part, you don't want to change jobs every 3-6 months if you have a full time job (stick it out for 6 months to a year and see how it goes) and you should be building on skills/ experience with each subsequent position.
Most MBA programs have average work experience at 5-6 years post-college. You may find you need that amount of time before an MBA makes sense for you, or less, or more.
aerienWhy Yale | My Advice For Younger Applicants