Hello and welcome to the forum
I know from my own experience how confusing it is for a newly diagnosed diabetes to know what to eat. The only way to find out is by keeping a food diary and testing your blood sugar before and 2hrs after eating, this way you will learn which foods make you spike and are best reduced or avoided altogether.
I think most people would find such a small pot of porridge too high in carbs, the only way for you to find out is to test your blood sugar before and after you have eaten it.
There is no specific rule for any of us, some people can eat potatoes and experience no blood sugar spikes, others spike into double figures at just seeing a potato from 5 miles away (ok I am ever so slightly exaggerating here). So it is a case of testing and learning the basics of diabetes.
Here is a link that is given to all newcomers to the forum
viewtopic.php?f=20&t=17088
Read around the forum, some of us are low carbing, some are managing very well on a low GI plan, some need medication, others want to control their diabetes with diet and exercise alone, there is no right or wrong its what you personally feel happiest with, there are several tools available for you to achieve good control. Learn about the different foods, I once was so insulin resistant that even a mug of tea with milk would make me spike, then I realised its the lactose in the milk, so I changed to lactose free milk and single cream instead, no more spikes after tea drinking for me.
One website that I found very useful and straight forward was blood sugar 101, links are not permitted in this forum, so google for it, there is lots of clear information for you there.
Ask questions, people are very caring and helpful in here.
All the best