That's total BS. I'll tell you a little story explaining why-
Svetlana Chmakova (born 1979 in Russia) is a comic creator. She is best known for her Dramacon Original English Language (OEL) manga published by TOKYOPOP, the 2-page The Adventures of CG for CosmoGIRL! magazine and the webcomic Chasing Rainbows for Girlamatic. Though born in Russia, she emigrated to Canada, where she graduated from the Sheridan College Classical Animation program, in 2002. She then began to publish her manga on the Internet, where her works were found by CosmoGirl! magazine.
Currently, Dramacon has been translated into 12 different languages, including Japanese, and has gained world renowned sucess. The Atlanta Journal-Constitution described Dramacon as "surprisingly true-to-life (and occasionally harrowing) emotional drama and humor ... Creator Svetlana Chmakova doesn't skimp on character development or plot progression. Her art is top-notch as well, outstripping even many of her Japanese inspirations with clear storytelling and polished technique."
Her current project, Nightschool, is being run in the Yen Plus+ Magazine, and has also been recognized for her talent in the manga-making world. Svet has also been asked to work on a new animated series called "My Life Me". And this is just the start of her career.
What I'm saying is: Don't let people keep you down from following your dreams. Just because someone says you can't achieve something, DOES NOT mean you have to take that to heart. Keep working on your manga. Never let anyone tell you otherwise :) I wish you the best of luck.