There are many things that could be the culprit:
If you are unsure, post a screen shot that includes the Layers panel and Page panel, both opened up so that we can see the contents. Click the triangle in front of Layer 1 to open it up. For example:
Use the button outlined in orange below.
Hi Wendy, are you still having trouble with the selection tool? Did any of Barbara's questions help solve the issue? Let us know if you need further assistance.