I have a project but don't know which language to learn

Hi All,

I have a background in the Heating, Ventilation and Air Conditioning field and would like to develope a program that would allow people to do load calculations on their homes for air conditioning sizing.

This software would be for sale and available for download from my site. I would like to be able to offer a demo download which would expire after one use or after a trial period.

I would like it to have a good looking interface and be user friendly.

Maybe this is not a good first project to learn programing but this is what I want to do.

I know HTML well enough to design a site and I know enough Javascript that I would not hesitate to play with some simple code to modify it.

Can anybody tell me which would be the best programing language for me to try to learn?

I am thinking Java but don't know if will be suitable for what I want to achieve.

Any advice would be greatly appreciated.

Best Regards,
Troy