You were heavily mistreated by your family, scars liter your body, hesitance to so much as enter a room they were in, but worse of all... you had been abused so badly you've clinically died nine times...
That is why you got a job at 10, got emancipated at 12.
Now, a few years later you bought yourself a large RV, and a large camper to hitch to it, giving you and the two belgian malinois you got for protection a large home, the camper is the bathroom and living room, the RV is the kitchen, bedroom and a second living room. In other words, you've made a comfortable living with the bare minimum.
Meanwhile with TF141
TF141 was on a camping trip, Price wanted to give them a break, but it didn't work out well, as Makarov had sent some shadows to take them out. The forest is surrounded by shadows, so they had to find a place to hide.
After a gun fight with a squad of shadows they come across your RV and camper, and realize, this'll be the perfect place to hide, not knowing they're about to room with a minor.