diff --git a/src/modules/auth/components/RegisterForm.jsx b/src/modules/auth/components/RegisterForm.jsx
index 7261106..c6c6cbb 100644
--- a/src/modules/auth/components/RegisterForm.jsx
+++ b/src/modules/auth/components/RegisterForm.jsx
@@ -17,16 +17,19 @@
  ***********************************************************************************************************************************************************************/
 import { useState } from 'react'
 import { useNavigate, Link, useSearchParams } from 'react-router-dom'
-import { useForm } from 'react-hook-form'
+import { useForm, Controller } from 'react-hook-form'
 import { useAuth } from '@/contexts/AuthContext'
 import { z } from 'zod'
 import { zodResolver } from '@hookform/resolvers/zod'
+import { format, parseISO, isValid as isValidDate } from 'date-fns'
 import { cn } from '@/lib/utils'
 import { OtpVerifyForm } from './OtpVerifyForm'
 
 import { Button } from '@/components/ui/button'
 import { Input } from '@/components/ui/input'
 import { Badge } from '@/components/ui/badge'
+import { Calendar } from '@/components/ui/calendar'
+import { Popover, PopoverContent, PopoverTrigger } from '@/components/ui/popover'
 import {
   AlertDialog,
   AlertDialogAction,
@@ -36,7 +39,11 @@ import {
   AlertDialogHeader,
   AlertDialogTitle,
 } from '@/components/ui/alert-dialog'
-import { Eye, EyeOff, LoaderCircle, Users, Check } from 'lucide-react'
+import { Eye, EyeOff, LoaderCircle, Users, Check, CalendarIcon } from 'lucide-react'
+
+// Birthday must put the user between 13 and 120 years old (mirrors personalSchema below)
+const MIN_BIRTHDATE = new Date(new Date().getFullYear() - 120, 0, 1)
+const MAX_BIRTHDATE = new Date(new Date().getFullYear() - 13, new Date().getMonth(), new Date().getDate())
 
 // ─── Step schemas ─────────────────────────────────────────────────────────────
 const personalSchema = z.object({
@@ -141,6 +148,7 @@ export function RegisterForm({ className, ...props }) {
   const [showConfirm, setShowConfirm]   = useState(false)
   const [errorDialogOpen, setErrorDialogOpen] = useState(false)
   const [errorMessage, setErrorMessage]       = useState('')
+  const [birthdayOpen, setBirthdayOpen]       = useState(false)
 
   // Accumulated data across steps
   const [personalData, setPersonalData] = useState({})
@@ -149,6 +157,7 @@ export function RegisterForm({ className, ...props }) {
   const {
     register: regPersonal,
     handleSubmit: submitPersonal,
+    control: controlPersonal,
     formState: { errors: errPersonal },
   } = useForm({
     resolver: zodResolver(personalSchema),
@@ -304,12 +313,44 @@ export function RegisterForm({ className, ...props }) {
                 <label htmlFor="date_of_birth" className="text-sm font-medium">
                   Birthday <span className="text-destructive">*</span>
                 </label>
-                <Input
-                  id="date_of_birth"
-                  type="date"
-                  max={new Date().toISOString().split('T')[0]}
-                  className="text-sm"
-                  {...regPersonal('date_of_birth')}
+                <Controller
+                  name="date_of_birth"
+                  control={controlPersonal}
+                  render={({ field }) => {
+                    const selectedDate = field.value ? parseISO(field.value) : undefined
+                    const validSelected = selectedDate && isValidDate(selectedDate) ? selectedDate : undefined
+
+                    return (
+                      <Popover open={birthdayOpen} onOpenChange={setBirthdayOpen}>
+                        <PopoverTrigger asChild>
+                          <Button
+                            type="button"
+                            id="date_of_birth"
+                            variant="outline"
+                            className="w-full justify-between font-normal text-sm"
+                          >
+                            {validSelected ? format(validSelected, 'MMM d, yyyy') : 'Select date'}
+                            <CalendarIcon className="h-4 w-4 opacity-50" />
+                          </Button>
+                        </PopoverTrigger>
+                        <PopoverContent className="w-auto overflow-hidden p-0" align="start">
+                          <Calendar
+                            mode="single"
+                            selected={validSelected}
+                            captionLayout="dropdown"
+                            defaultMonth={validSelected ?? MAX_BIRTHDATE}
+                            startMonth={MIN_BIRTHDATE}
+                            endMonth={MAX_BIRTHDATE}
+                            disabled={{ before: MIN_BIRTHDATE, after: MAX_BIRTHDATE }}
+                            onSelect={(date) => {
+                              field.onChange(date ? format(date, 'yyyy-MM-dd') : '')
+                              setBirthdayOpen(false)
+                            }}
+                          />
+                        </PopoverContent>
+                      </Popover>
+                    )
+                  }}
                 />
                 {errPersonal.date_of_birth && (
                   <p className="text-xs text-destructive">{errPersonal.date_of_birth.message}</p>