Should an undergraduate answer a call for reviewers? I'm currently a senior undergraduate student that has a couple publications where I've been 3rd author on conference papers. I've been conducting research in the field for around 3 years.

I got a call for reviewers from a conference that I've submitted and been accepted to before. I am unsure on whether or not I should answer the call as I don't know how much experience I should have before I can review papers. 

I know it would be good experience for me to get and something I am looking forward to doing in the future. However, I don't want to take this on without knowing what is expected of me. 

Some questions: 


How do journals verify your expertise for review?
Can I work with someone else to conduct the review (advisor)?
Are reviewers usually faculty?


Should I tell the conference leaders that I am an undergraduate and ask if I can still review papers?



Thanks and let me know if you need any extra info!
Normally a PhD (in my experience) will conduct their first peer-reviews with their supervisor or another academic. An undergraduate may (rarely) have the technical expertise, but reviewing is also a skill (that doesn't take long to pick up, but requires a bit of guidance). Poor reviews can waste time of committee members or, worse, harm scientific and academic output, and even harm your own reputation. On the other hand, if you contact a member of staff that would be an opportunity to learn how to do it properly and maintain or even advance your reputation at a very early stage in your career.