You really have to try and pinpoint the reason for your highs and lows. Keep in mind that for many T1s, puberty (which lasts most of our “teen” years) can really wreak havoc on BGs. The hormonal surges cause us to become insulin resistant, and this is made even more difficult when you’re a women and your hormones are changing on an almost-daily basis.
Are you properly matching your insulin to your carbs? If your I:C ratios are off, you will get lots of highs and lows. Keep in mind that your I:C ratios may be different at different times of the day.
Your profile says that you’re using a pump and I know for me the pump has given me better control. I still get highs and lows, but they are not as extreme. A high for me is now about 200 and a low 50. When I was doing shots, my BG would range from 40 to 350 on an average day. For me, this was because (as an adult) I am fairly insulin sensitive. HOWEVER, fine-tuning the settings on my pump has been a lot of trial and error (and mostly error). I’ve had to do a lot of logging and tracking and adjusting. It takes time, and I’m not sure how long you’ve been on your pump. It may be that your pump settings need adjustment. I’ve seen the biggest changes in my BG following changes in my basal settings, so you might want to work with your endo and look there.
Another thing that has helped me is sticking to a fairly low-carb diet. I eat about 100-150 grams of carbs per day. I avoid the foods that I know are problematic, such as white rice, pasta, and bread. Yes, I love those things and I know in theory T1s should be able to eat those things as long as they are properly matching their insulin to their carbs. But, for me, it just doesn’t work. I was able to get my A1C to drop a whole point by simply eliminating those foods from my diet. So look at your diet and see if there are foods that are causing you trouble. High fat/high carb foods are my worst enemy. I can eat high fat provided there aren’t too many carbs with the meal. I am sure this is different for everyone.
Finally, as Still_young_at_heart recommends, “Think Like a Pancreas” and “Pumping Insulin” are amazing books that will provide you so much information. Don’t Just Read Them Once!! Read them again and again…I had to read Pumping Insulin three times, and I still go back and read specific chapters on a regular basis. If you’re pumping, it’s a MUST READ.
Finally, realize that your BGs will never be perfect. You can get them into that good range which will give you the A1C you desire, but they are never probably going to be “normal people perfect.” That’s just how we T1s roll
Do you have a supportive endo? What is your endo recommending?