I'm not sure if what I doing right now is acceptable, or if it would just be tacky. I'm working on a novel, but... Having some issues with the POV. The story starts in third person, set in current time, as the introduction. It then moves on to first person, alternating between the two main characters from chapter to chapter. This is set in the past, about 5 years. Once I've said all there is to say on that, it moves back to third person and current time. Since the part set in the past (and in first person) is more than just a brief glimpse into the past (its going to be a detailed description of their lives as teenagers), would it be tacky to go back and forth like that? Too confusing? To noob-ish? Should I go through and rewrite everything into third person?
In general response to your question -- if the teenage-years stuff is crucial to the plot and an actual part of the storyline, then yes, include it; you'll be fine with that method as long as it's obvious to the reader which chapter is about which character. If it's all to convey backstory, though, slip details in naturally in passing. It's much more efficient and effective (90 percent of the time) than huge infodumps or history chapters.
My advice is to try both first and third person in one or two chapters (or just few scenes) of the portions you want to write in first person. If you feel that first person is the only way you'll do justice to the story, then go for it (as long as you have a good handle on switching POV). On the other hand, if writing it in third person (third person limited is similar to first person in many ways) also have the same impact, then you should stick to one POV. No doubt the readers will be jolted to a certain degree (the degree varying depending on how well you pull it off) when you switch POV. If you don't want to break the trust of the readers, your reasons for switching POV should be apparent and good. This is what you should think about if you are set on switching POV.
Personally I think I'd find the third person to be subsidiary to the first person sections, in general. I mean first person is what I always find most engaging, possibly because it tends to have the strongest voice, and so I'd tend to view it as the main storyline. But I think almost any variation of form can be made to work, and if this is the way the story needs to be told then don't force it into another format. My only worry with this approach is that it might be unclear which is the main plotline and which is subsidiary, but so long as it is made clear in the writing it shouldn't be a problem. I certainly don't think there's any intrinsic problem in switching between first and third.
