Well from what I have heard we will be pretty green compared to Shepard. Same for our squad. Shep and crew were veterans. We are trained but inexperienced.
Indeed - and maybe that's better? I mean:
More of a blank slate, maybe? (Better for people who roleplay!)
If they offer us more DIALOGUE-OPTIONS (again!), so that we can flesh out our character more and respond better to any given situation, than I am COOL with having a younger protag (despite being older than the protag...then again: I've NEVER felt the age I am, I felt older when I was younger (and behaved like that, too so I was quite the party pooper - no drinking myself to oblivion (and telling other people they shouldn't either), no just not doing homework, trying to keep the classroom quiet even if the teacher wasn't there (that's why I became the class representative/prefect several times)) and now I feel and empathize more with younger people (note: I am not out of my twenties yet, but almost!) because I've never been extremely serious (sure: restrained, mature - but never extremely serious) and gruffy like many adults (don't understand people like that, I just cant!)), hell:
I'd have voted for a younger protagonist if given the choice 
greetings LAX