I would take it out and do a good inspection. Get all up in there. From the tippy top to the bottom of the longest root. I would also twist those 3 effected leaves off:). Just in case. Almost looks like the leaves in that area have been sunburned. Other then that your Echeveria looks nice:).

Thank you, Kara ! But after the inspection, should I wait for another 10 days before watering or just following the old schedule (tomorrow is her first time being watered :D)

After you inspect her I would wait about 5 days to water. I have a feeling nothing's wrong, but it's best to be safe:). Looks like the sun fried it one day a long time ago.

It seems that sunburn is the case since it has been quite scorching lately. Last week the temperature was around 36 degree Celsius . About the roots, the plant has some new white roots while the other side of the foliage is nice and healthy :). Thank you again Kara for your wonderful tips :)))

No problem glad I could help. You have a beautiful Echeveria;).