Hiragana and Katakana

I wanted to ask a question I just started Rocket japanese this week. Prior to that I studied and memorized both hiragana and katakana so instead of writing in romaji I write with the actuall characters when i listen to the audio. usually listen the first time and then write it out in Hiragana/katakana as the lesson goes. my question is have I messed myself up be learning the characters that way???? I can listen to how its said and write it but friends of mine said that is wrong. please let me know

Konnichiwa! If you have memorized both Hiragana and Katakana you are well ahead! Romaji is not part of the Japanese writing system. The Japanese writing system consists of three sets of symbols: Hiragana, Katakana and Kanji. Romaji ("Roman letters") is simply Japanese written in alphabetic characters. You could become fluent in Japanese just by knowing Romaji, but if you want to go beyond books that are written in Romaji transcriptions, you should and must learn the Japanese writing system. The sooner you can read and write Hiragana, Katakana and Kanji, the sooner you can start feeling like a Japanese! So, knowing Hiragana and Katakana is essential to mastering Japanese- and it appears you've already passed that test! You haven't messed yourself up by learning the Japanese script! The Romaji is simply the alphabet characters you already know. -Sayaka