我这个程序为什么点击完按钮后mp3要过好久才播放？甚至不播放

Option Explicit
Private Declare Function mciSendString Lib "winmm.dll" Alias "mciSendStringA" (ByVal lpstrCommand As String, ByVal lpstrReturnstring As String, ByVal uReturnlength As Long, ByVal hwndCallback As Long) As Long
Private sFilename As String '获取文件路径
'/////播放声音
Private Sub pgmCmd_Click(Index As Integer)
Timer1_Timer
sFilename = (App.Path & "\word_Phonogram\" & Index & ".mp3")
mciSendString "Play " & sFilename, 0, 0, 0
Timer1.Enabled = True
Label1.Caption = "朗读：" & Index
If Index = 1 Then sFilename = (App.Path & "\word_Phonogram\1.mp3"): _
mciSendString "Play " & sFilename, 0, 0, 0
End Sub
Private Sub Timer1_Timer()
mciSendString "Stop " & sFilename, 0, 0, 0
Timer1.Enabled = False
End Sub