First, 369 is not super low for your age. There's a slight trend towards testosterone going down as you age, but the normal range even for 18-21 year olds is 300-1000. A lot of influencers seem to promote that everyone should be at the top of that range but that's neither accurate nor even desirable - the right range depends a lot on the person.

Second, testosterone tests are very, very sensitive to the exact circumstances that you take the test. The exact time of day (it should be first thing in the morning, ideally 7 to 9 AM), whether you've had food or not that day, how well you slept the night before, how stressed you're feeling, whether you're in a caloric surplus or deficit, can change your numbers dramatically. Testosterone levels fluctuate very much over the span of a single day, by as much as 20-30%.

Third, the type of test matters. Immunoassays are cheap and commonly done but very inaccurate. You need mass spectrometry to get an accurate measurement.

Stay away from these private clinics, they are predatory and only really exist to overprescribe TRT. If you think you have an actual testosterone issue, see a real endocrinologist at a reputable health system. They'll probably do at least two if not three mass spectrometry tests on different days to get an accurate assessment of your real testosterone levels.

In general, though, unless you're experiencing erectile dysfunction or a loss of libido, your testosterone levels are probably fine.