Retaking GCSE MATHs

I’m currently in yr 12 studying Econ, politics, psych. In my GCSEs I got mostly 8s and 7s and a few 6s but I got a 5 in maths w 5 marks away from a grade 6. In university most unis would want a grade 6+ to do an Econ or Econ related degree eg soas or city St George’s.

How fast do you think I’ll be able to get a grade 7 in 4 months I already know a lot of the content. And is it worth it?