The thickness of my hair strands vary on my scalp. Does this mean I am balding?

It certainly could - it just depends on how many hairs are miniaturizating. If it's just a few, it may have little meaning. It it's more than 20 %, it is very likely. Please see a physician for diagnostic advice.

When a hair is in the process of beling lost, it may go through a miniaturization process which will produce a thinner hair shaft.   Your biggest enemy is the progressive thinning leading to a balding pattern that may not evident at this point in time. The degree of thinning that you are experiencing would suggest that you should see a doctor who most likely will get Bulk Measurements of your hair to determine the degree of the thinning that you may be presently having. If the diagnosis is early genetic hair loss (the most common cause of hair loss in young men and you are probably following your families balding problem), then the best treatment would be the drug finasteride which is highly effective in men of your age and may no t only stop the hair loss but possibly reverse it. If you are developing a more advanced balding pattern the best test to get is the HAIRCHECK instrument test which will determine the Bulk Measurements of your hair and this will show, over a one-year time frame, how effective the treatment will be or if you are not on drugs, using this instrument to tell you if you have ANY hair loss at all.  Once you know this information, then you and your doctor need to develop a MASTER PLAN which will define what you need

hair miniturization is one of the early symptoms of hair loss. If you lose about 80-100 hairs per day is normal but if you lose more, you need to see a hair loss specialist.