They actually will take your school profile into consideration, so don't worry about that, just do intramural, maybe if you like to swim, get a life guard certification...just something to prove you are well rounded.
For those who are new, the school profile will show the background of the school, everything from grade scale, to clubs to how many go 2 yr, 4yr Private, 4 yr OOS, etc.
They try to balance everything so everyone is on a level playing field. they are not going to punish you because your school doesn't offer 15 APs or they have Beta over NHS against the kid that has every sport, AP and IB programs.
They want to look at how competitive your school and how competitive you are in that school, and than they start again from the national perspective.
For example, if you go to the number 1 school in the nation, and are in the top 30% with that GPA, but at your school the top 50% get into HYSPM, than that percentile will not hurt. However, if you are in the top 30% and the top 25% go to 4 yr ISS, that profile will hurt you when they go back to re-weight your academic review.
People also forget, that if they give a wgpa, to this board, you should also give it on what the scale is. 4.12 sounds great, but is that on a 4.5, 5.0 or 6.0 scale? Big difference, because more than likely the AFROTC board will re-weight you if it is 6.0 and it will drop big time.
The best way to see is if you order your SAT and ACTs to be electronically sent. At the bottom, at least they did it 2 yrs ago, they will show your school gpa, and the re-weight for the colleges you sent them to. If I recall correctly it usually is a 5.0 on a 7 pt scale for how they calculate their gpa.