How can I know if I am able to pursue a PhD?
Talk to your professors. They've been through PhDs themselves, and they know your capabilities much better than anyone else to boot.

Having said that, if you have both a very high GPA and research experience (which you did not dislike), you should be more than qualified to do PhD studies. If you aren't qualified then nobody else in your cohort is qualified, which is not believable. Besides, if you want to become a professor, you'll need to get a PhD - since it's something you must do, you might as well attempt it (or change career goals).