So this is something that I originally struggled with. I didn't know whether to write this current book in first or third person POV. oh the agony! There's obviously no correct answer and it's specific to your story, but I didn't really understand the difference and which one was used when.
The first thing I did was to look at books similar to mine, an adventure/fantasy story with romantic elements. Well, there were books with both POVs, so that didn't help much. I knew there wasn't a correct answer, but I still didn't know why someone chose 1st vs 3rd. I finally picked 1st, because I enjoyed 1st POVs better. Then I took a few writing classes and I finally realized the difference; that as the writer, I had to decide what the story is really about - the MC's internal struggles (1st person) or the outside events that were happening (3rd person). For this reason, adventure/action stories are usually third person. There are always exceptions, of course; the Hunger Games is in first person, though that had a lot of internal motivation. And I think Percy Jackson is in 1st person, though I read that I really long time ago and can't remember.
If you're still having trouble deciding which POV, another idea is to think about if different POVs are necessary. While multiple view points can be done in first person, sometimes it can get confusing. Is the other POV in first person as well? If so, make sure the voices of the characters are different enough, so that the readers can tell whose head they are in. Alternating between first and third is getting more common, though it can be tricky to make it believable. Usually if different POVs are present, the story is written in 3rd person.
In the end, I realized I like first person POV better because I liked being inside the MC's head and understanding the motivations, despite my story being part-adventure story.
Do you write in 1st or 3rd? Which do you prefer to write? To read?