Problem with Hlookup, Vlookup, Index with table

Everything I seem to come across in this forum is close, but doesn't exactly answer my question--but close.

I am trying to re-write an ARMY APFT scale. I have a table, many of the items in this table are similar but not all. The table is A1:K1 and A1:A77 (quite a bit of data) all located on sheet 2. Columns A1:K1 are ages--i.e. 17-21, 22-26, etc., etc.-- Rows A1:A77 are the number of repetitions performed--0 push ups through 77 push ups--you get the idea, I hope. The look up data is based off of the gender, the age, and the number of repetitions. But this data is on sheet 1. How in the world do I do this?

I figured it should be something like:
=IF('sheet1'!A7="M", Lookup(I7,'sheet2'!A1:A77,VLOOKUP(J7,'sheet2'!A1:K1---no clue at this point))

"M"=gender M/F
I7=repetitions
J7 which would be the age
Because I don't understand how to then look up both the age cross-referenced with the repetitions I am at a loss.

I would be more than willing to send someone the idea in the form of a spreadsheet so that "they" could look at it. Maybe the explanation isn't very clear.

**this is like trying to speak German in Italian**