she's at a fine weight for 6 months old.
weights will fluctuate as they mature and grow, their weights usually plateau once the glider turns one or shortly before or after they turn 1. That weight will be their "adult weight" and it still may vary a gram or two depending on when you weigh them.
When I get on a weighing spree I weigh them around 1 or 2pm before any treats and well after they last ate off their dinner plate to get the most accurate weight I can. I will usually make a list of everyone's weight for a week or two to see where every is at.
Bottom line she's 6 months old. still growing, her body is still filling out and maturing. I wouldn't cut back on fruits or treats even.
I actually have an obese glider, she's around 200 grams, there are ways to tell if they are overweight or where they should be.
Most people think if a glider has noticeable boobs ( male or female ) that the glider is overweight, that's not an accurate way to tell.
Gliders store extra fat in the chest area, it's a safe place for healthy fat storage in case the glider ever goes into torpor. When in the state of torpor, the body uses the stored fat to sustain the glider until it comes out of torpor. Think of it as an extra gas tank. The entire body slows down, heart rate, circulation, digestion, everything to conserve as much energy as the body can. It can be so drastic that owners have thought the glider was dead when it wasn't.
Unhealthy fat storage is in the "wing" or membrane. If the membrane feels thin and smooth the glider is NOT over weight, if the membrane feels thick, and uneven the glider IS over weight.
Please keep in mind, gliders body size, build, frame and weight all vary just like humans do. I have gliders from a 20 gram joey to 80 gram 6 month old, 70 gram 3 yr old 164 gram 3 yr old and varying weights in between all the way up to the 200 gram 3 yr old, who will likely always be over weight.
The only time you really should stress over it is if an adult glider is 50 grams or lower THAT is the danger zone. Personally my 3 yr old at 70 grams is to skinny in my opinion but she may never get any bigger and has potential organ damage from a severe allergic reaction to essential oils. I'd be happier if she gained 5 or 10 more grams but she's as healthy as she can be where she's at and I don't feel feeding high in fat foods to her will help her organs any so I don't. She gets fed the same as the other 3 in her cage ( including the 200 gram girl )
If I were you, I wouldn't stress about it she's just maturing