I would do a PCT now, then wait a month and get your levels retested. You can have low test and need HCG even without your balls being visibly shrunken. That happened to me, my test levels were 80 and my balls wer hardly shrunk at all. After another PCT, I am back at 520 with about the same size balls (I am 41 years old).
Here is a proposed PCT:
week 1: nolva 20mg ed
week 2-3: nolva 40mg ed, HCG 1000iu eod (for 10 days - 10,000iu total)
week 4-5: nolva 20mg ed
Optionally you can add this in, overlapping the above:
day 1: clomid 300mg
day 2-10: clomid 100mg ed
day 11-20: clomid 50mg ed
You can also try using 6-oxo (a widely available testosterone boosting supplement that from my experience works very well) after this PCT:
week 4-7: 6-oxo, 1 capsule 2x daily
week 8-9: 6-oxo, i capsule daily (tapering off)
Around week 11 or 12, get your natural test levels re-measured. If they are not in the normal range, only then consider HRT. It is highly unusual for a 24 year old to require HRT! You want to make that decision very carefully with your primary care physician (not an HRT doctor - they can be biased) and an endocrinologist referred by your primary doctor.