First of all wish you a very good luck for your new start.
Its never late to start something new. To learn programming I would like to suggest you, take some basic tutorials from w3schools.com
Also have a look at site themeforesr.net. here you will designs of every type. From here you gain more ideas to build site and implement them. Its more easy to download tempalte, understand coding and do some reaserch.
I wish you a very best luck for your new start. If you need any further assistane dont forget to ask me.
Congratulations on considering development as an addition to your career. It is indeed never too late to learn something new.
Please note that MySql was deprecated and you should learn MySqli instead, preferably the OOP (object oriented programming) format. Make sure that you are aware of mysql vulnerabilities because it is easily possible to write secure code.
A few functions that I recommend you to learn:
explode(); // Awesome for "slicing" text
implode(); // Awesome for combining text
$value > $nimber ? 'Value is higher than number' : 'Value is not higher than number'; // Not exactly a function but pretty useful to do more with less
Learn OOP as soon as possible because it is extremely helpful. Once you are experienced enough you should consider using a PHP and a UI framework as well (or develop your own).
Glad to hear you want to expand your knowledge. It's good to see people interested in this type of stuff and good to see how motivated and hard they are willing to try to take on a new lessons and to learn new things .
W3schools is a wonderful site for all languages after your done with them you may want to check out php academy from YouTube then php killer.net
These languages you want to learn are very powerful and good in their own ways. Best of luck taking on this assignment you got for yourself hope you learn the best and do good.