Is this structures of SQL models okay? (Flask)

I am creating a chat application in flask where you can create users and chat with others. I am storing all the information in SQLAlchemy. I was wondering if this structure for my models is okay. I am still a beginner with Flask and SQLAlchemy so I may have errors.

from . import db
from flask_login import UserMixin

user_chat = db.Table("user_chat", 
    db.Column("user_id", db.Integer, db.ForeignKey("user.id")),
    db.Column("chat_id", db.Integer, db.ForeignKey("chat.id"))
)

class User(db.Model, UserMixin):
    id = db.Column(db.Integer, primary_key=True)
    email = db.Column(db.String(150), unique=True)
    username = db.Column(db.String(150), unique=True)
    password = db.Column(db.String(150))
    firstName = db.Column(db.String(150))
    lastName = db.Column(db.String(150))
    birthday=db.Column(db.String(150))
    sport = db.Column(db.String(150))
    bio = db.Column(db.String(150))
    chats = db.relationship("Chat", secondary=user_chat, backref='users')

class Chat(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    messages = db.relationship("Message", backref="chat")

class Message(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    text = db.Column(db.String(300))
    username = db.Column(db.String(150))
    chat_id = db.Column(db.Integer, db.ForeignKey("owner.id"))

User class is the user schema. Chat class is the schema for the chats which contains many messages which are the Message schema. Should I change anything or is this good? I am still learning sql format so I am not sure if you're allowed to have Chat be connected to two tables? Thank you!!

source https://stackoverflow.com/questions/72049174/is-this-structures-of-sql-models-okay-flask