Neileg is absolutely right but didn't give you all the options you can use to assure proper data conformance. (I can't either, but I can add to the list.)
First problem is that the wizards are ... well, ... DUMB. But if you understand their options, you can help them make YOU look like a genius. This is a case where Murphy's Law is applicable in its full form. "When it can go wrong, it WILL go wrong." And the rest of that law is "So make it happen in a way that can't go wrong."
Instead of importing a new table each time, take this approach.
Create a table, call it TEMPTABLE, with the exact field structure you need. Create an Erase query that amounts to DELETE * FROM TEMPTABLE; and run that before each import. Then run an Excel import to an existing table rather than letting Excel create a new one. With the field types already defined, the wizard cannot go wrong unless the data in the table is wrong. And when that happens, it ain't your fault any more.
Next, if there are rows that don't behave well when imported, you have the chance to run a remediation query on your TEMPTABLE data BEFORE you attempt to append it to the live data in your master table. AND this way, it doesn't matter as much what the field names are in the spreadsheet. You could import everything as text and just trash that title-row record.
Third, if there is a format change required, you can to that in the Append query if you need to do so. Like dates come in as text but you want them as dates. Either the import to a temporary table will do that right or you can include a CDate$() function in one of the fields in the final Append query that adds the new records to your existing table. So if you imported all fields as text for screening purposes, learn the various conversions such as CDbl, CSngl, CLng, CInt, etc etc. Then you can write a meaningful Append query afterwards. If it doesn't work, you have the option of stepping back and trying again.