General Questions about getting started from zero

Hello I’m eylem,
2 days ago I decided to attend a web course, than I just discoverd codecademy, started a course into html and I loved it.
I could hardly believe how subjects are devided so systematicly to little easy understandable lessons.

My real education is architecture but ı’m working on my web based startup for 2 years.
I am the designer of my site by all ways-ı mean the mechanism of operation on the front side- but ı have no code knowledge. I draw the pages at photoshop, desciribe how it’ll work and our web developer firm makes it work. But taking support from a firm does not satisfy me no more. I want to be able to do everything myself-or at least to know how long it takes and how can it be done even ı personally can’t.

1.What ı want to learn is, if I finish all courses,at the end will ı be able to make anything ı need on my project not taking support from outside. I can share the link of my site needed anyway.

2.Is there a way to make practise on the data( a have my web sites all code document) of my site, practise on a copy of it on my computer? just yes or no is enough.

3.Is working on a code written by another one may cause problems ı can’t fix without help? I mean hidden work or source data ,purchased template or someting ı can’t reach how it’s done or revised.

  1. Is code something that anybody having education on it can read and understand everything done by other developers?

3I’m really excited and don’t want to leave my computer a minute. Can anyone inform me about my questions?

thanks already

  1. If you learn at least HTML and CSS (and preferably, some JavaScript if needed) then yes

  2. Yes, you could try to replicate the code made by your developer

  3. Well, you might not understand everything that was written from the get-go. It will take some time for you to assimilate all concepts and tricks used. Learning and practice will help.

  4. Yes, with time, you should be able to understand the work of other developers. If the code is written properly and using best practices, it might even help you reading and understanding it.

Hope this answers your questions.