Is it possible for me to gain muscle and maintain my body fat at 20%..

Whats kind of diet should i follow? Currently im doing full body for the past 2 month plus with a balanced diet..
Pls give me some advice n tips since im a newbie.. tq 

This is my current progress at 20% bf

For the past 2 month plus, my weight is stagnant between 73-74.5kg and body fat around 20-21%.
But my shirts are getting tighter.. I supposed either my weight or BF should change if im bulking right, why is mine stagnant? 

I can't provide an accurate statement regarding ur progress as I don't know ur diet plan nor do I know how much u eat a day , along with ur training routine as well. However, what I've observed from the information you've provided is that you may have probably hit a plateau. It is crucial to alter ur calories as u grow . If I may ask , do you calculate your calories ? (how much u should eat , ur TDEE , etc...). On an average joe , you should probably see an increase in 1lbs-3lbs a week (or less) if u're bulking , HOWEVER it really depends on how much of food you eat that will reach ur needed calories . Any amount exceeding 3lbs per week or more MAY consist of more fat than muscle gains. SIFUs correct me if I'm wrong here.

Yeap , therefore u won't be a fatass if u bulk then cut  .