Advice on Progress so Far

https://community.myfitnesspal.com/en/discussion/10332083/which-lifting-program-is-the-best-for-you/p1

Here you go. I agree that you need to be following a proven program. A couple things jumped out at me from your description of your program.
First, static stretching has been shown to be counter productive based on recent research. Better to do dynamic stretching using the exercise you are going to do with lighter weight.

Second, you are doing curls and forearm and wrist exercises as part of your program. Pretty useless for gaining mass and are really considered auxiliary lifts. To gain mass your focus wants to be on the big muscles, quads, hamstrings, glutes, pecs, back muscles and shoulders. Fine to do curls as accessory. Unless you are training for a specific purpose, wrist exercises are unnecessary.

Designing programs requires knowledge of physiology and kinesiology. Most of us neither have the knowledge or experience to do that. You certainly don't and that shows in your program.

Go through the programs from the above link and find one that utilizes body weight exercises and dumbells and do that for now. And make sure you eat enough calories and protein. And be patient. It takes time.

In your photos, it is evident that you gained some mass. As a young newbie, you can pretty much do anything at this stage and gain some mass if you are eating enough but that doesn't make it optimal.