My aunt is the executor to my grandmothers will and I'm concerned that she is going to sell my grandmother's house,and somehow cheat me out of my rightful portion of the estate.Would it be wise for me to file a Lis Pendens?

No. Filing a lis pendens saddles you with the potential liability for wrongfully interfering with a sale.

Your best bet is to contact a California attorney about making sure that any sale has to be approved by a court after notice and opportunity to be heard are given to you. In some states this is called "supervised administration".

Has your aunt been required to file a bond, and is the amount of the bond sufficient to protect your interest in the estate?