How can I retrieve the first row of a file I am loading with SSIS to a variable in the SSIS?

Assuming you have TextFile connection on your Package.
Add a script component - Source.
Inside Script Compoenent Editor: In the connection manager pane, select your text file connection, and name it as "SourceFeedTextConn"

Create Required Outputs in Input and Output pane. say MyType1Output, MyType2Output , add required columns to each output

/* Microsoft SQL Server Integration Services Script Component
 * ScriptMain is the entry point class of the script.*/

using System;
using System.Data;
using Microsoft.SqlServer.Dts.Pipeline.Wrapper;
using Microsoft.SqlServer.Dts.Runtime.Wrapper;
using System.IO;

[Microsoft.SqlServer.Dts.Pipeline.SSISScriptComponentEntryPointAttribute]
public class ScriptMain : UserComponent
{
    private StreamReader textReader;
    private string SourceFeed;

    public override void AcquireConnections(object Transaction)
    {

        IDTSConnectionManager100 connMgr = this.Connections.SourceFeedTextConn;
        SourceFeed = (string)connMgr.AcquireConnection(null);

    }

    public override void PreExecute()
    {
        base.PreExecute();
        textReader = new StreamReader(SourceFeed);
    }

    public override void CreateNewOutputRows()
    {

        string nextLine;
        string[] columns;
        string type="";
        char[] delimiters;
        delimiters = ";".ToCharArray();

        nextLine = textReader.ReadLine();
        columns = nextLine.Split(delimiters); //all header
        string header = string.Join(";;", columns);
          // Analyze the header here
          if (header.IndexOf("MyType1Col1", StringComparison.InvariantCultureIgnoreCase) > -1
                    && header.IndexOf("MyType1Col2", StringComparison.InvariantCultureIgnoreCase)> -1
                    && header.IndexOf("MyType1Col3", StringComparison.InvariantCultureIgnoreCase) > -1)//and so on)
               
             type="MyType1";
           if (header.IndexOf("MyType2Col1", StringComparison.InvariantCultureIgnoreCase) > -1
                    && header.IndexOf("MyType2Col2", StringComparison.InvariantCultureIgnoreCase) > -1
                    && header.IndexOf("MyType2Col3", StringComparison.InvariantCultureIgnoreCase) > -1)// and so on)
        
             type="MyType2";
          //and so on
       nextLine = textReader.ReadLine();
       while (nextLine != null)
        {
            columns = nextLine.Split(delimiters);
            if(type=="MyType1")
            {
                 MyType1Output.AddRow();
                 MyType1Output.MyType1Col1 = columns[0].Replace("\"", "").Replace(";", "").Trim();
                 MyType1Output.MyType1Col2 = columns[1].Replace("\"", "").Replace(";", "").Trim();
                 //and so on
            }
            if(type=="MyType2")
            {
                 MyType2Output.AddRow();
                 MyType2Output.MyType2Col1 = columns[0].Replace("\"", "").Replace(";", "").Trim();
                 MyType2Output.MyType2Col2 = columns[1].Replace("\"", "").Replace(";", "").Trim();
                 //and so on
            }
            //and so on
         nextLine = textReader.ReadLine();
        }
    
    }

    public override void PostExecute()
    {

        base.PostExecute();
        textReader.Close();

    }
}

Now Add add destination components and connect each output of Script component to each destination.

Let me know if you need any help.

Thanks,

Kuthuparakkal