Hi sadieelliott.
From what I have seen, some schools may question an applicant's readiness to handle the quantitative aspects of the school's curriculum if the applicant scores below 40 on the quant section of the GMAT. Not all would, but many would. In fact, some schools would prefer to see a GMAT quant score in the mid 40's.
At the same time, there are multiple aspects to an application, and further, I have seen someone who scored Q38 make a deal with a school such that they accepted her on the condition that she take a quant heavy course before attending and get a high grade in that course.
So, really, the answer to whether you should retake partly depends on the schools to which you plan to apply. They may be fine with Q36, or that score might make getting accepted rather challenging. It may make sense to do some research or to contact the schools to find out.
At the same time, the truth is that, even for someone who has not historically been strong in math, driving up your GMAT quant score can be pretty straightforward. You just work topic by topic, strengthening weaker areas by learning all about how to answer a particular type of question and then answering dozens of questions of that type, and, basically, drive your expected quant score up point by point. By using that approach, you could drive your quant score up to whatever level you would want to drive it up to. Yes, time is a factor, but in theory at least, you could score 51 in quant by just learning one thing after another.
I'll add that increasing a quant score is easier for most people than increasing a verbal score. So, with your already strong verbal score, you are well positioned to score high on the GMAT.
If you decide to retake, you could get a sense of how to drive up your quant score by reading this post, which explains in detail how to do so.
How To Increase Your GMAT Quant Score