Funny I was just the reverse.
I got to Taris at 19 (or was it 17) and I just finished yesterday at 24.
All I did was the quests which are all solo.
No Space missions.
I did do one 4x but that is about it.
There are a ton of quests there.
Granted a hole new line opens up when you go to your ship for a story line and there the governor asks for more help. Maybe you missed a line of quests.
In the end I would say Taris is on Par with Coresant for number of quests.
You did taris at 17-19? You pro.