This OC belongs to Joceyb23

Name: Smallflower
I love this name so much! Usually I don't like cats being named after their size or disabilities, but this seems quite charming. 5/5

Past Names: Smallkit, Smallpaw
Alright 5/5

Name Reason: Small because she has a small frames body, and flower for.... No significant reason
Contrary to a lot of other raters, I don't mind the name not really having a reason. I kinda like the idea of the leader being like "Flower sounds nice, I guess" 5/5

Appearance: Light brown tabby she-cat with Amber eyes. As said above, she is small framed, and she's had a nick I n her right ear from a training session that didn't end well. Smallflower's fur is short, with dark tabby stripes.
The nicked ear is a nice detail. I really like her appearance, but there's always room for improvement! 10/10

Gender: Female
Noice

Age: 31 Moons
A decent age for a warrior 5/5

Personality: She's and introvert mostly, but is okay with being around other cats. She's not shy, just likes to be alone. Smallflower believes she has to be the best warrior in SunClan because her mother is the leader.
This sounds like me 0-0. The leader as her parent is a little cliche though, but since it's fueling her ambition it's fine 10/10

Sexuality: Straight (The only non-straight characters I have so far are bi) Not sure if you want more LGBT characters, but if you do, I like to take random characters and put them with other characters to see what fits. I also make characters whose gender I can't remember gender fluid or non binary.

Clan: SunClan
Founded by Sunstar (not canon Sunstar); territory mostly deciduous forest, camp is a large circle of trees, ranks and traditions mostly the same as canon clans.
First FanClan! I actually had a SunClan once lol. Anyways I really like the description, but I'm curious what's different about their ranks and traditions? 10/10

Rank: Warrior
Obviously 5/5

Mother: Dawnstar- Dark brown tabby she-cat with Amber eyes (Leader of SunClan)
Looks like Smallflower. I like it

Father: Adam- Pale gray Tom with blue eyes (Former loner, now SunClan warrior)
Nice base, but more description please!

Brother: Braveclaw- Pale gray Tom with blue eyes (Warrior of SunClan
'Brave' is kinda of a weird prefix. Was their mother like "I hope he's brave when he grows up, so Bravekit" or...

Family Score: 8/10 The missing details docked you a few points

Crush: Adderfur- Dark ginger tom with green eyes (MoonClan warrior)
Pretty, but guess what I'm gonna say next......... More description 4/5

Mentor: Ivyleaf- Blue-gray she-cat (SunClan Warrior)
Where's her eye color? And my usual detail complaints 3/5

Best Friend: Moonwhisker- White she-cat with ginger patches and green eyes (SunClan warrior)
This is optional, but I try to avoid having cats with the same prefix as a Clan. And why was she name whisker? Also more detail 3/5

Backstory: Even as a kit, Smallflower knew that she had to be the best. As an apprentice and as a warrior, Smallflower trained harder than any cat, attempted to catch the most prey, and patrolled every border she could. However, as a young apprentice at a Gathering, she met another apprentice named Adderpaw. He was funny and kind, and Smallpaw wanted to be friends with him. Once she was on a solo hunting patrol by the MoonClan border. Adderpaw found her and they talked and played for a few heartbeats.... Until the rest of Adderpaw's patrol found them. Smallpaw was taken to the MoonClan camp, and was let go after some stern words from Flamestar, leader of MoonClan, about love.
Smallpaw and Adderpaw thought that was hilarious. They weren't in love! Yet, after awhile, after the two became warriors, Smallflower began to fall for him. One night, they met alone on the border. Adderfur told her he loved her. But Smallflower knew that this was wrong, and she rejected him. She was loyal to SunClan only. Smallflower still crushed on Adderfur, but that didn't matter. Her Clan did. And one day, just like her mom, she would lead SunClan.
Nooooo! I wanted them to be together!
And is it just me, or does her desicion remind you of Leafpool? I like how she decide her career was more important though. I also really like how you said she 'attempted to catch the most prey' instead of she did catch the most prey. To me that implies effort and perseverance so I like it. Also why is her mentor never mentioned?

Moving on. The overall story could maybe use more detail. Did she have any other friends? What did her mom think of her so far? What about her brother? What happened after she rejected Adderfur? Maybe she became super depressed for a short period of time. Idk. 16/20

Total: Your total is 89/105! Almost a 90! That pretty good in my opinion. Some of things I had a problem with though is the lack of description for her kin/friends, and the short backstory. Try adding scenes that build up to the main events you got in your backstory already. Like why was she given a solo mission? Was it a reward for.... maybe catching the most prey, or winning the most at sparring? Things like that.