I don't think anyone could give any advice that would alter your opinion. French and English are sufficiently different that there won't be any confusion between the two, and if you have the time, energy, and patience, there is no reason why you couldn't learn both languages simultaneously.

I am studying 3 at the same time and speak English my native language and also Spanish. It definitely slows down your progress. It depends on what your goals are. If you are learning for fun, then it doesn't matter, but if you need one of the languages for work or a specific purpose, you should stick to that one. I am learning Portuguese , Italian, and French together. Portuguese is very confusing with Italian. It is not a good idea for those two. French is different from other Romance language and I do not confuse it with the others. I agree that French and English are very different and would not be confusing. However, as I said before, studying the 2 together will slow down your progress in each.

If you learn 2 languages at the same time, then try to choose those which are not similar to each other. Otherwise it will most probably be confusing. I mean you will not be sure which word refers to which of the 2 languages, you will also not be sure which grammatical form or rule is from one language and which is from the other. Here are the examples of such lanuages which are similar to each other in many ways and I don't recommend you to learn them together: Spanish,Italian and Portuguese. (The ancestor language is Latin for all the 3). French also came from Latin but it has specific features so I think it's possible to combine learning of French with such languages as Spanish, Italian and Portuguese. Russian, Belorussian and Ukranian (All are Slavic languages) Chinese and Japanese (Japanese came out of Chinese)