Scored 315 on my first timed GMAT mock — need realistic preparation advice

I’m a 27-year-old Indian professional with a BBA (8.7/10) and around four years of product-management experience. I work full-time, five days a week.

I recently attempted a timed GMAT mock without preparation and scored 315: Q64, V72 and DI60. I come from a non-mathematical background, and the score has affected my confidence. However, I’m willing to study consistently for four to six months.

I struggle with using multiple resources, so I need one structured course that teaches concepts from the basics and provides a clear study plan, practice and revision. My maximum budget is approximately INR 35,000.

I’m considering e-GMAT, TTP and CrackVerbal. Which would be most suitable for someone starting at my level? I would especially appreciate experiences from people who began below 500 or had a weak Quant foundation.

Should I spend 10–15 days rebuilding arithmetic through selected Class 6–8 NCERT chapters before beginning GMAT preparation, or should I start directly with a GMAT course?

My long-term goal is a strong international MBA for Fall 2027, preferably with a scholarship, followed by leadership and entrepreneurial roles. I understand that 315 to 755 is an enormous gap, so I’m looking for realistic guidance rather than guarantees.

What score improvement would be realistic in four to six months? Also, do you believe an international MBA will remain worthwhile over the next two to three years?