Regarding speaking in tongues, the Bible never tells us that we must speak in tongues. A good passage is 1 Cor 12:27-31:
The obvious answer to his rhetorical question (in bold) “No, of course they don’t!”. This idea is picked up earlier in 1 Cor 12:7-11, where different gifts are given to different people as the Spirit determines. This is a really clear answer from the Bible (yay!), the Bible doesn’t tell us that we must speak in tongues.
Which brings us to the second part of your question about whether Christians who speak in tongues are some how superior to those who don’t, or whether we’re missing something. Back in the first passage the last verse says that we are to “eagerly desire the greater gifts” (V31). But V28 tells us that they are more like the gifts of apostleship (which you and I aren’t!), prophecy, teaching etc… In fact, tongues are last on the list! The gift of administration is even above tongues in this ordered list. Sometimes it’s easy to over-emphasise tongues because they look impressive, when really God values other things more highly.
Don’t get me wrong, tongues are still a gift from God and still good, but the exact problem the Christians in Corinth had was that they played a game of one-up-manship based on who had the better gift, and who followed the ‘better’ Apostle - and that’s why Paul hammers them in 3:1 as “mere infants in Christ”. Don’t let whether you speak in tongues or not shake your confidence in Christ!
Finally, I think it’d be really good to be encouraged by what Christianity is all about. Have a read of this:
If you have Christ, you have it all!! That’s worth remembering I think.