The dolls far out way the concerns of the first time worries. Yes there seems to be a hole that is missing and you can purchase some TPE and plug the end or modify the doll as you see fit. Experiment, enjoy all positions and learn to take care of this one as if it was your first girlfriend. I find that managing the hair has been the most challenging. I have the 156 which is standing, the hips are stiff so opening and positioning the legs have been challenging at best, which is standard for those type of dolls. If you want something looser get one that isn't standing.
After getting Kimberly I have compared it to other dolls and the perfect one for me would have features this one doesn't. The vagina is not perfect by all means so taking note on the positions you like it might be difficult for doggy style unless you are willing to be creative. Other than being sexual the beauty is on par if not better than a doll costing 4 times as much. My favorite time with Kimberly is hugging her in bed as I drift asleep. I put on the electric blanket on low, crawl into bed and hug her tight and she feels so damn real. Best sleep in my life over the last 2 years.