There is a quest you missed, though only one. After you do it Aleena will be happy to teach you herbalism.
I believe that where you need to go for this quest is mentioned in the tutorial, when that Dermorian lady talks to you about magic, but it's probably a part that you could accidentally/intentionally skip. You also might want to check the welcome letter, if you ever received it and still have it.
Should you need help, people in game tend to be fairly happy to help you, and even running around like crazy talking to NPCs can be surprisingly fruitful at times.
At any rate, good luck... and may the Crystal light your path.