i will type date value in format dd/mm/yyyy or dd/mmm/yyyy, and calculate value return me different please give me solution

VBA Code:
Private Sub Command6_Click()
Dim paymentamount As Currency, totalpaid As Currency, x As Long, curdate As Date

If MsgBox("Are you sure?", vbYesNoCancel) <> vbYes Then Exit Sub
'clear existing payment schedule
CurrentDb.Execute "DELETE FROM LoanpaymentT WHERE LoanID=" & LoanID
'Loanpayments
paymentamount = LoanAmount
totalpaid = 0
curdate = StartDate
For x = 1 To Nummonth
    'If x = Nummonth Then paymentamount = LoanAmount - totalpaid
CurrentDb.Execute "INSERT INTO LoanPaymentT (LoanID, PaymentDate,paymentamount)" & _
        "Values(" & LoanID & ",#" & curdate & "#, " & paymentamount & ")"
    curdate = DateAdd("m", 1, curdate)
    'totalpaid = totalpaid + paymentamount
    
    Next
    
    LoanPaymentF.Form.Requery