This is something I think about whenever Rarity, Pinkie, and Fluttershy hang out, and Applejack and Rainbow Dash hang out. Whenever they split up and Twilight isn't there, they seem at home with there friends. What was life like for them before Twilight showed up?
Well, here's my head cannon, BOMBS AWAY!
Twilight's life isn't much to speak on, she was a typical school filly with a brother she looked up to and had little time with "friends". =No friends
Rainbow moved from Cloudsdale to Ponyville and took on a job as a weather pony. Perhaps because she controls weather, Applejack had met her, because she is a farmer. One the topic, Rainbow Dash really like Sweet Apple Acres cider, she has always liked it, and it sounded like she has been trying to get some for years. If memory serves me right, Twilight has been in Ponyville for almost a year to a year and a half, and Rainbow said "Every year" this would be more than one or two for her to say something like that, seeing as it would have to be a pattern, and a pattern would be noticed after at least three times. Once is not a pattern, twice is a coincidence, three times, something is up. Anyway, Rainbow could have managed weather over Applejack's farm for years for all we know.
=Coworkers with Applejack, Knows Pinkie Pie, Childhood friends with Fluttershy
Applejack was in Ponyville for her whole life, so it wouldn't be weird if she knew a lot of ponies. Pinkie Pie works in a bakery, and lives there too. She needs food for her parties and is known to be a party planner. This would have us believe that she also knows a lot of ponies. Applejack knows Pinkie, because Pinkie is a consumer (on that note, Rainbow doesn't know Pinkie very well and avoids her as seen in "Griffon The Brush Off" because she sees her as annoying and bothersome) Applejack might know more ponies as consumers than friends, seeing as though she often works alone and is less likely to just "hang out". Rainbow might be a friend of hers, but that would only be in Rainbow was the only pony working the weather over the farm, and as far as I have seen she works everywhere and is not controlling just one part of Ponyville, as to say, the weather over the library is the same as the weather over the farm. Applejack also has a pet dog that Fluttershy walks.
=Coworkers with Rainbow Dash, Knows Pinkie Pie, Knows Fluttershy
Rarity and Fluttershy have been friends for a long time, as said by Rarity herself. When they go to the spa during "Green Isn't Your Colour" Rarity says (in a nutshell) that this is something they have been doing for a long time. Considering this is an earlier episode, this would be less than a year of knowing Twilight. Usually I wouldn't go to a spa with someone I knew for less than a year on a weekly basis for my own reasons, and this won't apply for everyone, but I'm just going to add a little personal self into this. I'm guessing (with a sprinkle of personal thought in the matter) that they might have been best friends for almost a year or two. But Rarity has always been in Ponyville, and Fluttershy got there as a filly, so maybe much longer. Pinkie is also friends with these two and this is seen in "Putting Your Hoof Down". This may be a relatively new friendship, considering Pinkie is very loud and may scare Fluttershy, and has a lack of taste in style, turning Rarity off. But it's food for thought.
=Rarity and Fluttershy are long time friends (longer than Rainbow Dash) and Pinkie is a new best friend
Furious Flyer Dashie OUT!
P.S. Next time, I will be doing pony ages and maybe connecting the social dots of how ages effect ponies in Equestria!