49 years T1 here, still active and healthy. I know I'm lucky to have got away with it, but I spent my entire teenage years high (how high I have no idea as it was pre glucometer, but I sure felt thirsty on occasion).
And even though I now test 50 times a week, I still get highs. On occasion, and I pull them down fast, but being T1 is what it is. And I'm doing better now, maybe one 18 a week, and my endocrinologist is more worried about lows. (Actually, I'm doing really well about hypos at the moment, and I prefer 1 18 a week to 4 hypos a week.)
But everyone is different. Try not to be discouraged by the T2s who can achieve normal blood sugars by going low carb. It's great for them, but they have a different illness. The fact is that there are many T1s on here who live into their 70s, 80s and (90s?) with blood sugars that average significantly above normal.
It's an illness, yes it impacts on your life expectancy. But the technology (even if it's only a glucometer) is there to minimise that impact. My mother was T1 and made it to 78 (in 2012), with the first 30 years pre glucometer. (She was diagnosed at 20). And it wasn't the diabetes that killed her, it was the nicotine.
You don't have to be perfect to live a long and healthy life. Just don't ignore your diabetes, but don't let it rule you. It's one of the few illnesses where the patient has more control than the doctor. When first diagnosed it's scary, particularly if you get inundated by horror stories from Dr Google. The fact is that 100 years ago it was a death sentence, but since then it's been increasingly manageable. Current technology is marvellous, young diabetics are in a very good place. Just don't expect your blood sugar to be in normal range 100% of the time. Maybe in another ten years they'll have the technology to do that, but it isn't there yet. And it doesn't need to be. I've been living with a promise of a cure in ten/twenty years since I was eight years old, and it isn't relevant for me now.
So that graph isn't great, but at least it doesn't include a night hypo. If it repeats, it's probably a lack of basal, but I can do graphs like that just by over indulging in cheese (sigh, I love cheese, but it does fatal things if I have too much at night. Other people cope fine with it).
Aberrant readings are depressing, but the main thing is to work out what caused them.
Good luck.