People need to remember that your backstory details was very open in FO3. You are not necessarily the natural son or daughter of James and Catherine, not by any means. For example, Catherine may have been [censored] by a raider and then rescued before being killed for food.
The only thing you are restricted to in FO3 is that you are 19 (in vanilla) and that you are American. The latter point is a standard in all Fallout games due to the setting, at least in all games to this point. Excluding the idea of being an illegal immigrant or an immigrant who is in America on a work or student visa, or some other type of legal residence in America at the time of the Great War, you are an American regardless of what racial background you may have.
Likewise, at least from what we know so far, Fallout 4 has you as an American who is a young advlt perhaps mid-20s to mid-30s, unless there is something where you could be much younger or older). (sigh... very unfortunate, but hopefully mods will fix this). You are also (apparently) married, although the details have not been given yet so there may be some variations on this element. For "variations", consider how the "significant other" shown at the beginning may not necessarily be your legal spouse because it might be that your actual spouse is dead and a brother/sister has taken you and your young baby in. We don't know that level of detail, at least not yet. You are not an illegal immigrant nor someone here on a work or student visa, at least not from what we have seen. Other details also remain unknown despite the assumptions that people are making on various threads and comments.
Regardless, OP, you need to remember that an RPG is not about playing yourself as a character, but rather about playing a role OTHER THAN yourself. An RPG is the exact opposite of what you claim in your opening post. If you want a game where you play yourself, it would not be an RPG. Role playing requires playing a role that is not oneself. I have pointed this out in other threads/comments, but the anology would be acting and auditioning for a role in film or theater. If you audition for a role and attempt to play yourself, you will not be offered the role and will fail the audition. Likewise, if a game emphasizes or even requires you to play yourself, it fails to be an RPG. It may be a great game in other respects, but it is not an RPG. The problem, of course, is that there are no true RPGs on the market today, and the products offered as "role playing games" are, at best, hybrids of action-RPG or strategy-RPG. We can blame the market and capitalism/business requirements, but that's where we are at today as far as RPGs are concerned.
A voiced protagonist (and voiced NPCs, as well) have been standard in the industry since the 1990s. BGS is simply (finally) catching up to other companies. This is their first attempt at something that other companies have been doing for decades, so we'll have to see how well they do it (i.e., offering a role for us to play, including allowing lack of details to give us flexibility in defining the background elements of the role).