I need help deciding what I should I should evolve eevee into. Like I do..

You can evolve your Eevee into a Jolteon, or Umbreon. They're very good Pokemons.

I would eveolve it into an espeon

Well this is what I would do,look at each Pokemon,heres a review.
Espeon:Great Speed and Special Attack,combine with a Twistedspoon,makes a good Special Attacker
Umbreon:GREAT Annoyer,great Special Defense and Defense,give it some moves like Toxic,Confuse Ray,Moonlight and Faint Attack and you got a great Annoyer right there
Jolteon:Like Espeon,Great Speed and Special Attack,Electric attacks are great
Vaporeon:Good Special Defense,Water Attacks are great
Flareon:Also good,Fire attacks and Special Attacks are OK

My suggestions are that you take either Espeon,Umbreon or Jolteon.

Evolve to Jolteon/Vaporeon/Flareon, because you can import Umbreon and Espeon from Pokemon Colosseum if needed.

Umbreon all the way

Pick umbrion I completed it with that one or keep it as evee I completed it with that one to

Espeon forever- Psychic rocks! Great Sp. Attack and Speed makes it one of the best attackers in the game- I can KO Greevil's team with JUST my Espeon, at Lv. 50 like Greevil's. It's great. But, after all, it's your choice.

Your choice( maybe you should save first then choose and check there stats if you don't like it turn off the game and try again)

Save before you choose and then when you choose look at the stats and if you don't like it then turn off the game and try again(remember it's your choice)

I would pick pick vaporeon or jolteon because the are both good Pokemon and you can import umbreon and espeon from Pokemon Colleseum.

Try Umbreon if you want to because he has only 1 WEAKNESS witch is ghost types and they are the most RARE types in the game. And if they appear just kill it with Teddiursa or something.
Well it's your choice and if you want to experiment save then take one and if you don't like it turn off and try again.
Message too Umbreon:xox