If you are level 17, you're currently on track for level 100.
Your quests have contributed for 5 levels if you're on the standard path or 10 levels if you're on the extended path.
Objective for next week: Level 25
Being on the track is just an "average" value for players starting the Journey on the first day of the Journey and playing regularly. You can be ahead or late compared to the value, this is just to give you an estimation on where you should be to finish the Journey on time without any rush.
You can use
No reward above level 100?
After level 100, you get 2 reward points per level, but you can get a lot of extra reward points by completing some contracts tied to Aretuza's Cosmetics. Most of those contracts can be completed after the end of the Journey.
Some contracts you can do right now:
[Extended] Play 10 games with any Aretuza Theme
[Extended] Play 40 games with Headmistress' Office Board
Source: https://www.reddit.com/r/gwent/comments/p6018f/aretuzas_journey_week_3_youre_on_track_if_you_are/