I would probably not use Excel for data  of this quantity, however, others would.

I wouldn't say that databases are much more flexible at things like column
insertion - provided you've set your Excel code up properly in the first place.
You should be using named ranges or column headings or lookups to locate your
data columns, rather than simple column letters.

Excel is good at statistics and graphs, so that's an advantage.

Excel isn't good at lots of different views of the same data - databases are
better.

However, it's up to you. Both technologies can be made to do the work.

The problem is that you've jumped right in the deep-end, with a technology that
you are inexperienced with. You will need to have the patience to rework as you
learn.