Skills are way more important than what program you use.
A professional artist can most likely do stunning work in Inkscape, Illustrator, Corel Draw and other programs.
Adobes program are almost considered as standard in the business but cost A LOT.
Personally i find Inkscape much easier, more fun and faster to do what i need to do than using Illustrator and produce the same quality.
I've seen people make amazing graphics in Inkscape, and also seen others make horrible graphic in Illustrator... so
I know professional artists who prefer Inkscape for 80-90% of their work and only use Illustrator when needed, just because they prefer the cleaner and more user friendly Inkscape to Illustrator.
If you get a job as a graphic designer in the future it's more likely that that company use Adobe programs than open source programs.
On the other hand.... a graphic designer isn't something you become over night... it takes years and thousands of hours practicing and you will use and test many programs along the way.
If you like Inkscape and Gimp now, just keep using them and work on your skills, your work will speak for itself... no one can tell what program you've used any way.
Good luck
