I want to know if I purchase InDesign if my current Pagemaker files will transfer in without any problem?
They will not open in CC; but will open in CS6 and earlier. There are always text reflow changes possible when you change versions.
ID 6 supports pagemaker files, but as Michael says, lots of errors occur when opening the files. Text reflow changes, the way images are handled is completely different.
Best way to work: start again from scratch if possible.