Well I guess the correct use of cases (and tenses) will be the most challanging for someone speaking English as a first language. Latin has six destinct cases and three genders (masc. fem, neut.) and genders rarely go with the "natural" gender - meaning that things are not neutral gender as in English.
I have no idea how Latin will be taught with you methodically but however as with every language you will start simple and go into more complex grammar later.
My advice is the following: Make sure to stay up-to-date with learning - doing a little every day is much better than let it run and try to catch up buy learning lots of stuff in very short time.
That way you can build up a basic knowledge which you will never forget.
In my old school
Latin was the second language we had to learn (first one was English) - not counting German which is my native language. Although my last Latin lesson is back more than 25 years and I did have to use it very little since then the basics are still there.
Although it will start really simple with sentences like
Sicilia est insula - Sicily is an island
make sure you stay current - it's maybe a little bit like eating: Regular small portions are better than one big portion once a day.
I hope you will enjoy Latin although you will have to work for it but it can open a world for you that lies back more than 2000 years but is the basis of European culture (and languages)
Sorry - I guess that was a little bit longwound.