Comming indoors for night time

Alice the naughty tortie (but adorable) is 8 months old now and had her since 7 weeks. Had always kept her inside until she was speyed at 6 months, she was bursting to get outside and released her to the great outdoors at 7 months. She loves it out there as she is so full of energy and just goes crazy, she still comes inside to check in about every half hour just to see me, have snack or curl up on the bed for a while. Have had 4 cats throughout my life and have always kept them in at night, need to do it especially with Alice as shes already been bashed up 3 times by neighbourhood tough toms who are always on the prowl at night and lucky during the day although wounded I've been able to rescue her. So all's well until about 10pm when I use her final meal for the day to lure her back in for the night, started 2 weeks ago she eats her meal then hides somewhere dark instead of joining us in the lounge like she used to. She makes herself very hard to find even when I think I've checked everywhere and wont come when called until I rattle her Katzini treats. If shes happy to hide then I dont mind but wondering if this is just a phase she will grow out of? am I upsetting her keeping her in at night? has anyone else experienced this behavior and know why she does it? Around 5am shes back to herself and comes on my bed for snuggles. Have yet to introduce ourselves on "New cat on the block" once I work out how to attach a picture. Glad to of found this site full of other caring people owned by cats.

Many thanks for your encouragement, I will keep it up I just feel bad depriving her of her night time frollicks and bug catching, shes still a real baby, hope a few months on she will return to the lounge with us, shes gotta get bored with hiding in a dark place.

Weird is putting it nicely, phsyco comes to mind after trying to figure her out these last 6 months, lucky I just love her sooo much.
She is very typical of Torti shell with a serious attitude, been labeled "wildchild" at the Vet, but has some very nice qualities starting to shine through and shes a real character, starting to show affection and even letting me hold her for more than 3 seconds.
That idea of outside enclosure sounds real good, am in a rented house so theres not much I can modify but you've given me a great idea for the next house we are hoping to buy. Many many thanks!!

After the nice feedback and encoragement I recieved, I decided to hang around and wait while she finished her meal so that I could follow her, when she finished she went to the door then to the window to find outside access denied she meowed her resentment went under the dining room table jumped onto the chair and up the sleeve of my dark heavy motorcycle jacket, she stayed squashed in there for an hour till I lured her out with her favourite treat and ball games. So I came to a conclusion that this behavior seems to be a form of sulking relating it to what a child would do when they dont get their own way. So anyway have decided to try and distract her attention away from outside access after her meal with her games and hope she gets over it in time, fingers crossed!!