Did you call it right? Sure! It's your job to bend the rules or those you don't agree with to make it fun and enjoyable and reward clever tactics.

Did you do precisely what the written rules dictate? No. Here is why:

Divine Sense

Until the end of your next turn, you know the location of any.....not behind total cover. You know the type of being whose presence you sense, but not its identity.

'Location' or: A creature's 'Space' PHB pg. 191

A creature's space is the area in feet that it effectively controls in combat, not an expression of its physical dimensions. A typical creature is not 5ft wide, but controls a space that wide.

Mirror Image

Three Illusory duplicates appear in your space. The duplicates move with you and mimic your actions, shifting positions so it's impossible to track which image is real... A creature is unaffected if it can't see, if it relies on... blindsight or if it can perceive illusions as false, as with truesight.

Now that I've cut these down to the parts we should be paying attention to, we are left with the following conclusion with no real argument to the contrary:

A humanoid celestial angel is perhaps 2 foot across in width, but it controls a space of about 5 feet. That's its personal space, its combat space. A humanoid is not 5ft wide folks. This is its location. That particular 5ft space within its control.

Mirror Image places 3 illusory images of that same celestial in that same space. The same location. They move with the celestial, nearly imposing themselves with the celestial as to make themselves seem like an after image. Think of this as someone moving their hand in front of a high speed lens and leaving behind an after image of their hand that follows split seconds behind their real hand. A mirror image as the namesake of the spell suggests, making it impossible to track which image is real. What the spell is saying it DOESN'T do is create 3 copies of the celestial that all stand around/beside/next to said celestial like "Hi, how are you doing, which one of us do you want to hit?"

Divine Sense allows the Paladin to open up his senses and divine the location, the effective space, of a celestial that is not behind total cover. They know for all intents and purposes that there is a Celestial in that effective space, that location, but they can't identify the celestial specifically. Just that it exists.

Let's put this into the setting. There is a Celestial that seems to be moving so fast that there are 3 other images of itself that mimic its every move and action. I can't tell which one is the right one because they are so close together in its space, its location. The Paladin uses Divine Sense. "Yep, there's definitely a Celestial right there, but because the mirror images are mimicking its every move so closely together in its space (its 5ft location), I can't really help pinpoint which one is real. Swing and hope you hit something!"

Lesson: Divine Sense is helpful for finding invisible creatures of the effected creature type, or figuring out if there is one in disguise parading around in some other form. Something that counters magic, such as Dispel Magic, is better for something like Mirror Image, as are AoE attacks.

No, mirror images aren't enemy creatures

Sneak attack requires "another enemy". Mirror images aren't enemies different from you; they're in your space, and they "move with you", so they don't present additional threats.

In general, there's no strict definition of "enemy" provided in the PHB, but it's often used interchangeably with "hostile creature". So, as you continue to find ways to enable Sneak Attack for your Arcane Trickster, consider the Sneak Attack rule to be:

You don’t need advantage on the attack roll if another creature hostile to the target is within 5 feet of it, that creature isn’t incapacitated, and you don’t have disadvantage on the attack roll.

Mirror images aren't hostile creatures, so this won't work. RAI for allowing sneak attacks without advantage when an enemy is adjacent to the target is clearly that sneak attacks are facilitated by the rogue supplementing other party members in combat, so low-level illusions don't cut it. Note that you don't have to be in melee; you can stand back and snipe with missile weapons while your ally gets in close.

(As a general suggestion, I would work on using your Arcane Trickster's spells to buff yourself/teammates and make ranged sneak attacks rather than trying to make melee sneak attacks work without teammates to help you).