Do you feel like you are going to be competitive in regards to commander's ranking after only being there a semester? From my understanding this is a big portion and probably very hard to make much of an impression in only a semester. As for the ACT and GPA that doesn't seem to matter on only being in ROTC for a semester. Also do you feel like you were able to prepare yourself for the AFOQT with only a semester of ROTC classes or did you spend alot of your own time playing "catch up" in regards to AFOQT knowledge.
The AFOQT really isn't a big deal, if you did well on the ACT or SAT you'll do fine on this. There is no AF specific knowledge on it, the only sections you may really have to study for are the Pilot and Navigation sections if you plan on going for a rated slot (pilot, RPA, CSO, etc.). It's basically just the AF's version of the SAT/ACT. If you look it up you can see all the sections and what is on them. There are strict rules about studying for it that you may want to look up, but basically there is no studying with another person, using previously owned study material, and no one is allowed to help you study for it or give advanced knowledge.
As for CC ranking as a 250, last year the EA slots given at my det were about 50/50 for 200s and 250s, many of the best cadets had just started that year. Just go hard, get involved, volunteer for stuff, and don't be afraid to speak up. It's good to join ROTC extracurricular like Silver wings or Arnold Air Society, it's a great way to get face time with the people who will be evaluating you (POC, cadre members). Organizations like that are good if you want to get involved, but you certainly don't need to join them in order to get a good ranking. In fact there are cadets in SW and AAS that in the bottom 1/3, so extra face time can be a good thing or a bad thing. Tech majors have an advantage, idk your major but as long as you can keep a high gpa, have good SAT/ACT/AFOQT scores (they take the higher of the 3 composites), high PFA, and are active in your detachment you will be just fine.
Trust me, there are 200 cadets that have been there since day one who have skated by and stayed in the background so much that the cadre and POC barely remember who they are. There are 250s that are super involved and seem like they've been there forever and there are 200s that make you wonder why they are even still here. If you perform well, your ranking will reflect that.