Been asked to peer review, unsure as to qualifications?

Assuming this is a reputable journal, then I don't see any problem, especially if the manuscript is in your areas of expertise. It is this expertise the editor seeks. It is not how long you have been in academia. A good editor will seek multiple opinions. Since you have published in the same area, then you are in a good position to provide useful opinions.

Editors usually do a Google search to find people who have published in the same area. Alternatively, the manuscript in question may have cited your past works. Also, editors tend to have their personal pool of reviewers. Any papers assigned to them will then go these reviewers. Lastly, the journal submission system may maintain a pool of reviewers or past authors and their expertise.

If you have been asked then go ahead, you could check with them. Do consider that they may have chosen you as you may be more "current" in that particular field than some of their "standard" referees.