Yes!  Thank you!

ならう means like specifically taking lessons from someone else or at school.
maybe you mean 勉強(べんきょう ) which means studying

勉強している
is what i think you mean.
You don't want to just use a past tense like naratta cuz then it means you're done doing it, you're not doing it anymore. Use a -te form +iru/imasu to show that you've been doing it and you're continuing studying Japanese.