1) I think you'd look awesome with a nose piercing - pay no heed to the person who said your nose is too big; people with big noses can often be the best looking with nose piercings, as they can define the shape of your nose, take away attention from certain details, and look pretty and delicate compared to a piercing which occupies the entirety of a tiny nose.
2) The hole is miniscule - the people who say it's big and noticeable must have been looking at some seriously strange piercings! Nose piercings are done with a 0.8-1.2mm needle, and the hole tends to shrink to about 0.8-1mm anyway (which looks even smaller in person, because of the shape of the fistula). Honestly, I take my nose ring out every day for work and when I come in with it in they always ask if I just had it done, and I wear 1.2mm jewellery.
If you want it done, go ahead and have it done, it's your body and your decision. If you don't like it, it's as simple as taking it out.
Good luck!