You can prepare and appear for the CAT or any other management entrance test and pursue an MBA. Although you have three years of gap, there is no need to worry about this as you will be given an opportunity to justify it during the Personal Interview process. Now, in order to justify this gap, you can do some certificate courses, work in an NGO, pursue something related to your area of interest, etc. This gap year will not directly impact your selection chances in the business school but you should have a valid reason to support you answer. Apart from going for an MBA, you can also look for a job or can appear for any other competitive examination.