Is it worth it going for a doula Certification?

I would say no. But, it depends on how long it will take you to start midwifery school in earnest. If it will take you 10 years to start midwifery school, then why not?

However, if you plan to start school soon, then go ahead and take the doula training but forego the certification process.

I worked as a certified Lamaze CBE and an uncertified doula. No one ever asked me if I was certified and I don't think not being certified impacted my ability to be a good doula.

I'm in the process of becoming a DONA-certified doula, and I am also planning to become a CNM in the relatively near future (within the next 5 years or so). I decided to pursue the doula route as a way to decide if attending births is what I need to be doing, and for me, it's important to become certified because then people know that I've followed a certain, somewhat rigorous, program and process. Do I necessarily think that certification = best qualified/most compassionate caregiver? No, I don't; those depend on a lot of different factors, including individual personality and how the doula and the mom-to-be interact. But I think that going through a certification process does indicate that you are committed to the field and will likely be committed to your clients and will have the background to help them find the experience they're looking for. I would also say that even if you don't think the certification process is for you, at least look at the recommended and required reading for certifying agencies like DONA International and ALACE (which does both CBE and doula certification). Reading all you can about birth empowerment, natural childbirth and pregnancy, breastfeeding, and other related topics can be very helpful while you work through your own perceptions and conceptions of pregnancy and childbirth and your feelings about the two very different models of childbirth that are at work in our society. However you go about it, best of luck to you in your journey!