Only half of my dogs ever "asked" to go out, and it wasn't any of my Labs. I would just keep them on a routine for about the first year and set them up for success. They've all been trained with very few accidents.
As adults, unless it's an emergency they have all just held it until I let them out, which is on a routine even as adults, though routine is a little loose after a year old. And the way they ask has always different. Pacing. Staring. Sitting and looking uncomfortable. Staring at the doorknob. I guess at a certain age when they have things down pat, they figure out what gets your attention and then they stick with it, but it takes time for them to do that and time for you to figure out their sign.
The goal at this age isn't to get her to ask, it's to go outside. I think it's too early to ask for anything else and yes, it is normal. She is still just a baby. Still growing, still developing, etc. Stay on your routine and she'll figure it out, but it takes time. One thing at a time. A co-worker left his puppy with the breeder until she was 16 weeks because he wanted the puppy to come potty trained and she is peeing on the floor and I'm certain it's because they aren't on the same exact routine and his expectations of her are too high (and possibly the breeder made some empty promises).
The bells can work, though often they ring them when they just want to be outside or get attention and I think that's annoying, personally. Lots of boy crying wolf. And of course, the one time you call their bluff they go on the floor.