I have decided to run the marathon for the first time this summer. I started running like 2 years ago. I have run half-marathon in November, with a time of 1:41. I normally practice twice a week, running around 12km, which takes me from 00:54 upto 1:05 depending on my mood. I wanted to know if the training I am pursuing is good enough or do I have to start covering more kms per week?