But even with this it doesn't seem to pause and wait. In the code below, it should bring a matrix of InputFields and then when you increase n (main entry variable), it should Insert a row in the matrix, but it doesn't:
Clear[f, kk];
T = {}; kk = Null;
InputField[Dynamic[n,
  {n = #;
    AppendTo[T, n];
    If[Length[T] == 1, A = Array[c, 3 n],
     If[Length[T] >= 2,   
      DialogInput[
       DialogNotebook[{TextCell["Where to insert new rows? "], 
         InputField[Dynamic[nm], String], 
         Row[{DefaultButton[DialogReturn[kk = nm]], 
           CancelButton[]}]}]];
      A = 
       Flatten@Insert[A, Table[c, {i, 3 ( T[[-1]] - T[[-2]])}], 
         3 kk]; Print[kk];
      ]
     ];
    Print[kk];
    Print@
     Grid[Table[{"Amp", i, " = ", 
        With[{i = i}, 
         InputField[Dynamic[A[[3 i - 2]]], FieldSize -> Tiny]],
        "\[Mu]", i, " = ", 
        With[{i = i}, 
         InputField[Dynamic[A[[3 i - 1]]], FieldSize -> Tiny]],
        "\[Sigma]", i, " = ", 
        With[{i = i}, InputField[Dynamic[A[[3 i]]], FieldSize -> Tiny]]
        }, {i, n}]];
    f = Sum[
      A[[3 i - 2]] *Sqrt[2 \[Pi]]
        A[[3 i]] PDF[NormalDistribution[A[[3 i - 1]], A[[3 i]]], 
        t], {i, n}];
    Print@
     Show[ListPlot[gr3, Joined -> True], 
      Plot[f, {t, -1.8, -1.10}, PlotStyle -> Red]]
    } &]]
Not sure I understand why.