According to her Dad, Heather's first senior tournament will be at Clearwater in Florida in March, (see 4 mins into the interview on the following link).
http://news.bbc.co.uk/sport1/hi/tennis/7857978.stm
Looking at the ITF website, the only tournament taking place in Clearwater, Florida is a $50,000 event that starts in February. It that's the one it's quite a big tournament to start your senior career at.
http://www.itftennis.com/womens/tour...ent=1100019089