Hi!

I suggest you to create automated actions ir.cron, schedulers are automated actions that run automatically over a time period and can do a lot of things. They give the ability to execute actions database without needing manual interaction. Odoo makes running a background job easy.

Bellow, an example, adapt it as you need:

    <record model="ir.cron" id="check_birthday_cron">
      <field name="name">Check Birthday</field>
      <field name="model_id" ref="model_my_model"/>
      <field name="state">code</field>
      <field name="code">model.check_birthday()</field>
      <field name="interval_number">1</field>
      <field name="interval_type">days</field>
      <field name="numbercall">-1</field>
    </record>

class MyModel(models.Model):
    _name = 'my.model'
    _description = _("My Model")
    _order = 'date desc'

    @api.model
    def check_birthday(self):
        partner_ids = self.env['res.partner'].search([('is_member', '=', True)]).filtered(
            lambda x: x.birthday.day == fields.Date.today().day and x.birthday.month == fields.Date.today().month)
        for partner_id in partner_ids:
            partner_id.active = False

Best regards!