I've been a Baptist and a Reformed Baptist.
Reformed Baptists are much more biblically focussed, although if you are in the UK they will not teach the creation story as fact, but more of a general 'broad brush strokes' picture.
They are Calvinist, so people are saved by faith and divine grace, not by works. the bible is the work of God, and is to be studied and absorbed.
The youth club will most likely be a glorified Bible study - I actually learned a hell of a lot from the ones I went to! The pastors and elders are generally extremely well-educated and will refer to the original aramaic/greek/latin etc.
Whilst Baptists in general may focus on the New Testament, Reformed Baptists see the Old Testament as just as important, as it is the Old Covenent, which, although it was swept away by Jesus, is worthy of study and helps to know how God would like us to live.
Baptist churches can sometimes include people who speak in tongues or prophesy (this is probably particular to the area you live in), a Reformed Baptist church will have none of this - they believe that these gifts were all part of the Early Church only, and that prophecy and other gifts of the Holy Spirit have now ceased.
Baptists do tend towards the evangelical, but Reformed Baptists in my experience were less so, in that you have to come across them somehow - they don't actively recruit, and so many of their churches can be very small. They tend to have been breakaways from Baptist churches that they feel have become too worldy or otherwise departed from the word of God.
Reformed Baptists are extremely strict, but having said that, I loved the church I attended, and it was one of the few places I felt safe as a teen.
Things may have changed in the intervening years, but that was my experience in the 1980s/90s