Sacarlet: thanks.
As for "database coding" I think you will find that not to be so much of a problem. Especially if you have been working with large spreadsheets.
Yes you can make or have the database become very complicated and involve macros, VB code, scripts, etc..
On the other hand trying to make a spreadsheet behave as a database can become convoluted and cumbersome. Even though spreadsheets now provide many database like features/functions.
For example take some large spreadsheet that you have and import it into a database. (Note: you can link directly as RO but for learning purposes and to protect original data use importing. Besides if things go astray just delete the database table and try again.)
Anyway once the spreadsheet data is imported to a database table then you can use database wizards to create queries, forms, and reports based on that database table. The wizard results can be a bit much sometimes. For example, Reports (when printed) can use up a lot of paper unless you perhaps edit the report and take out extra spacing. Becomes more art than science (coding). Yet as you learn you can go into code and modify things directly. Using a wizard works very well with a simple application or can be a good starting point (e.g. a form) for something more complex.
Very sure that you have your hands full as it is and that I fully understand. Just do not sell yourself short and underestimate what you can learn to do. I have seen too many massive spreadsheets that grew out of some fear, distrust, or misunderstanding of databases.
Key is to do some reading about database basics and try a couple of simple databases. And once you get the sense of it all and do things such as linking (data in spreadsheet, queries /searches, and reports via the database) you will be able to set up a customer management system that will be powerful and flexible.