Hi there Hvzel!
I played the demo ver of your game and saw that you asked for feedback so here's my opinion to what you have so far!
I don't really know how RPG maker works so I'm not sure which things you used actually belonged to RPG maker. But I really liked the designs of my surroundings (inside houses, outside, etc), since I've played many RPG games and some of them were really poorly made when it came to that category.
I also really liked that you could enter all the houses, and the layout of the first map when we left our house was very simple and I liked that.
However, a point where you could improve is the story telling. I understand that this is a demo ver, but I was feeling a little lost. In the beginning when we discovered the crystal on the staircase, I was a little confused as to why it was there. And later on I knew my objective was to find my brother, but the note he left was a little random, since he only said he was leaving and never said why or where he is going.
Also the 3 year timeskip was very confusing and left me with a lot of questions (for example: why did we wait three years?).
Remember this is just my opinion. I think it's impressive that this is your first game. I just think it needs a little improvement in the story. Other than that I liked it! I hope this could help :)