Hi Liz, I am assuming that you have read the "stickied" threads, as you have been around for a coupla months.
The negative notations you receive sometimes seem to be working against what you are trying to do. Of course, you have to seek credit to get the credit, so you can't fret about that one. You should get another revolving card and keep that balance reporting $0 (you can use it, just PIF before statement drops). You will see a score increase when it starts to report.
Of course, you can't do anything about when your dad got that gleam in his eye toward your mother. Your age will definitely affect the age of your credit report. That's life and nothing you can do about it (other than becoming an AU on your grandmother's 40 y.o. Sears card).
Your scores will vary between the three CRAs because the FICO algorithm that they all use is slightly different. So, even if all of the items on your credit reports were reported exactly the same, you would see a difference in score on all three. If your scores happen to be the same, I would consider that more of a coincidence than anything else.
Hope this helps.