Hmmmmmn...I've known people to take on newcomers when they really shouldn't have...maybe too busy with others they sponsor, or their own lives. For whatever reason, they accept and then can't fulfill the commitment. NOT YOUR FAULT!
I've been asked, and had to decline...but, always tried to steer the newcomer to someone else who could sponsor them.
Start looking around for someone else as soon as possible. This obviously isn't working out, and she can't be honest enough to tell you...maybe she's afraid you'll feel rejected. This is your program, your life, your choice...not a "marriage - 'til death do us part". Good luck!