your prob around pre diabetic range... take it a little sooner and see how high it gets. but if 7.8 after 90 minutes thats prediabetic (of course ur machine could be off a bit).. your body raises blood sugar natural in the am even though fasted.( im no DR, but perhaps can give some info so can look it up yourself). large swings in blood sugar is sort of linked to diabetes ie from full on hypo to over 7. so keep an eye on things and maybe check ur A1C just to be sure aren't pushing yourself into diabetic ranges.. if blood sugar shoots super high right after eating and has to work super hard to get to high 7s after 2.5 hrs its getting borderline from my limited understanding, as thats what causes ur pancreas to start to wear out. ESP if your eating pretty clean and lower on carbs.. anyway, keep testing, keep a record(fasted before and after eating), as im sure want to avoid needing insulin as most people do unless professional body builder as simply not worth it. im no picture of health but for reference am fasted for ~12+ hrs its ~5.2 do little cardio still fasted drops a few points (although perhaps larger glycogen stores from not being on point), the girl gets cranky and hypo y at 4.4 and after eating grapes never gets over ~6.5. me aswell never get over mid 6 no matter what I eat or how long I sat around.(have grandma and dad got the type 2)
keep a record for a week or 2 with testing often fasted am, before u eat and 1-2 hrs after eating. but ya 7.8+ @ 90 min is prediabetic range, before meals is 4- 5.9 (so range of 2, not 4 as those 2 tests showed ur having), so if checking prior to supper and in or above 7s thats not "ideal". 7 is 129mg/dl for our usa friends 7.8is 140 for reference. while no serious immediate issue if skirt lower pre diabetes, just may not work out great as u age, esp if ever "let go".
a shit tonne of resources online about diabetes, and not trying to over emphasize and say ur gunna have diabetes in 4 months, just something to watch.