Well, how long ago was 7th grade? JK I always think a person can do whatever they set their mind to as long as they have the physical and mental capability. Therefore - go buy some fabric and get busy!
You'll need a machine - doesn't have to be the best for now. If you like it and want to do other things, you can invest in something nice later and donate or sell the first one. Fabric stores have dog clothing patterns in the craft section of the pattern books. Those can get you going and the instructions are pretty easy to follow. Just take your time, go slowly and be patient with yourself. You can do it! And use those resources at work. They'll be happy to help you.