You do not necessarily need to purchase a specific curriculum for kindergarten math. To recognize shapes and practice matching, you can either use ready-made worksheets or workbooks, or make some of your own.
If you do not understand the common basics of algebra then you will literally be lost forever when it comes to this subject. Being lost in the early stages of algebra can be disastrous because there are many years of advanced algebra just knocking on your door. Once you become more confident and your comfort level increases, you can actually strengthen it by trying to apply simple algebraic applications to everyday life. You will soon find out that algebra is not quite as difficult as you may have once thought.