I think you did very well with the actual perspective and having all the things aligned and going properly to the vanishing. There's only one thing that I think may not be completely accurate and it's the proportions of everything.
So the way I like to do it is to insert a ''character skeleton'' in the picture to check the proportions of things compared to a human. There would be 2 ways to tackle this. The first one I did is using the chair as a reference point. The seat of the chair should be slighlty below the knee and the full height might change, something around the crotch can work. So from that you can build a full figure.
So with this done, you can now move the full body measurement on the back wall, and it shows that the room looks abnormaly high. I believe a room is usually around 2.50 meters tall (so around 11 or 12 heads high). So unless it's what you were going for, you might need to correct the room height.
The other solution is using the back wall as a reference to build the figure. So using the back wall you can divide it in 11 or 12 parts and your guide figure would be 8 parts high. If you do it this way, then when you move the figure to the level of the chair, you will see that the things in the foreground are too small in comparison.
I think it would probably easier to correct this using the first way as you won't have to really rework the stuff on the right wall that you've already did.
I hope my drawings aren't too messy and that they make some sort of sense. You definitely undersatnd the basic of perspective, you just need to make sure everything is in proper proportions.
Oh and by the way I'll be 30 too next year too 
