Are you an old earth creationist?
How is that different than a theistic evolutionist?
Serious question: I honestly don't know.
OEC's believe that Darwinian evolution did NOT occur, that the evidence for antiquity of the universe is overwhelming, old age is not equivelent to evolution (that's a myth created by evolutionists who appeal to time to solve their problems and by young-earthers who have bought into the evolutionist's claim that antiquity is a evolution "proof"), the literal Adam, the special creation of man and animal life, that a literal and consistent interpretation of the Bible requires OECism. Etc.
Thiestic evolutionists (TE) believe God created the universe and let it go and allowed evolution to take control. Some TEs believe God occasionally interacted with the universe after letting it go, some do not. Some TEs believe there are signs of design in the universe (like OECs & YECs do), others do not.
There are actually a variety of creation views that don't support evolution (however, some YEC theories on animal speciation after the ark actually require some very fast evolutionary processes!), here are the four main ones:
Four Views of the Biblical Creation Account
These articles compare YECism and OECism:
Ten Major Similarities Between Calendar-Day and Day-Age Creationists
Ten Major Differences Between Calendar-Day and Day-Age Creationists
It's really like any other Christian topic, there are various theories considered acceptable by orthodox Christianity, but most people are familar with what they grew up with.