Well first off, did you ask why? You said "my mom and she said no most likely because our hobby room is a mess." Did she actually say because it's a mess, or are you just assuming that? If you didn't actually ask her why, then do. Listen to what she has to say. Maybe the room is hard to keep warm in the winter due to poor insulation, or she is worried you will sneak out at night. Maybe she doesn't want to have to move all your furniture.

I would first just sit down with her and talk to her like an adult. Ask her if you'd be able to talk to her when it's quiet during the evening, or during dinner. (Better yet, surprise her by cooking dinner!)

Then tell her again that you would really like to have the smaller room. Maybe even have a list written down (that you would be happier, that the large room makes you feel uncomfortable, you would like the coziness of the smaller room, you like how the windows face the street, etc. along with reasons why having the hobby room be in your current room would be better-there'd be more space so it'd be easier to keep clean, we could have more storage space, etc.) of why you want the smaller room.

Then you should say how you'd be more than happy to clean out and organize the hobby room this weekend, and that she doesn't have to give you a decision now. Then actually clean and organize the hobby room really really well. She might be more inclined to say yes, if you put forth all the effort to clean the room.

If for some reason, she is dead set against you having it,then I'd make the most out of having a big, rectangular room. I'd set it up like a studio apartment. Have one half be your sleeping area, and have another half be a cozy hang out/lounge area for your friends. Have lots of comfy pillows, beanbag chairs, round bowl chairs, etc, on a soft shag rug. From what I've gathered, all you need are string lights hung across the ceiling and it'll look tumblrish.

we always want we don't have so make the best, put a room divider at one end and make it a media room or just rearrange your room in the middle of the room work with it call a friend or aunt and check out idea's on the computer good luck.

Okay so this may be odd but I hate that my room is big. I would like a smaller, unique shaped room (mine is a rectangle) and we have a room how I like it and we call it out "hobby room" because we keep all of our art and crafts stuff in it and it's the perfect room for me, it's smaller, shaped unique, and even better is that the windows face the street, and I can climb onto the roof and stuff (I like to do that often) but I asked my mom and she said no most likely because our hobby room is a mess but frankly I would spend all day clearing it out if it meant It could be my room. But I honstly believe I will be much more happier if I had that room. I'm also into a tumblr indie theme, which work a lot better with a small room. What should I do? Or any advice for my current room?

Please no hate like "quit being selfish" or "get over it others would love a big room" I do not have any siblings and the only ones living in the house is my mother and I. I have always had a preference of smaller rooms.