Have I lowered my A1C enough? 28y/o (F) , low BMI, pre-diabetes.

In November 2017 I had a blood test with Hba1c result at 6.2%. I was 27 years old at the time, weighed just 49kg (153cm so normal BMI), and a 25 inch waist. My only risk factor is a family history (paternal grandmother type 2 in her 60s, and my Dad was prediabetic in his 50s).

Following the result, I completely changed my diet and lifestyle. Previously, my diet was largely based around wholegrain carbs brown rice, oats, bananas, lentils, beans and starchy veg (with occasional cheese, fish, chicken, biscuits and cake). Now I eat a low carb diet (avg 50-60g carbs a day) with a big focus on green leafy veg, chicken (and livers), turkey, oily fish, tofu, eggs and nuts / seeds. The only fruit I eat are strawberries or raspberries. I stopped eating biscuits (cookies) and cake and cut down on alcohol. I will occasionally drink beer (2 pints per month), or eat bread / pizza/ rice etc if I'm at someone elses house (about twice per month). Lentils and beans are still also included in my diet (as long as I'm not over 60 g carbs that day). I increased my exercise frequency, intensity, and duration (walk avg 5 miles p/weekday, and 7 miles weekend day and do 3 x 1 hour of resistance training in the gym per week) . I ended up losing 7kg, and now I weigh 42kg, and my waist is 23.5inches.

Last week I got my a1c results back. It's at 5.4%. I'm overall relieved that it's lower than a year ago and now in normal ranges but was expecting it to be much lower. Should I be worried that it's on the high side of 'normal' considering my current lifestyle and weight? I'm just worried that even if I continue with my current lifestyle, that my a1c will slowly creep up.