Nice one Belle! :-)
Well done Belle. I am very happy for you. Your niece is very fortunate to have you.
Teenage boys can be very challenging, as they are hormones with legs who feel like they should be treated as adults but are still kids.
Its a delicate balance.
I was never a foster parent, but was in foster care when taken from my parents for abuse from time to time...and, well, I was an easy kid...but I saw some not so easy kids.
All I can say is to maintain perspective, and DO NOT TAKE WHAT THEY SAY IN ANGER PERSONALLY.
Respond, don't react, perhaps, is your new mantra.
They will (WILL) test you. If you come back with ANY reply that is negative, "you're made"...and will never be trusted.
The test may be calling you a whore, etc...and if you had been abused, being insulted etc, can make you have an emotional reaction...that you HAVE to squelch.
They may even wait to find your hot buttons, things that can set you off....they are smart that way.
If in the system long enough to be teens...they will NOT give you the benefit of the doubt...you have to earn their trust.
Think about YOUR scar tissue, and, try to imagine THEIRS.
I hear you. Sometimes what seemed a disadvantage in life becomes a strength.