Ah, Steve touched on what I was thinking as well.
In cases like these, I would say to just go ahead and pick the right target date for yourself. As mentioned above, there's usually next to no difference between the two... at first. However, as time moves along, the portfolio between the two should start to differ, and having such a large time frame will only amplify that difference....
The only factor I would consider here is your risk tolerance.... If you are certain that you are a conservative investor, I would go with 2050. If not, I would go with 2055. If you have no preference or are not sure, I say go with 2055.
But all this is just hair-splitting. The most important obstacle is already surmounted, and that is to get started in the first place (especially at such a young age). Big congrats to you!!
