That's usually not a problem. You can always schedule the reading of an element manually. And if you do that for the first repetition, it will not have any negative impact on the algorithm.

You can also put stuff in something called "pending queue" and then just pull it from there once you're ready for it.

Only for the subsequent repetitions the algorithm will take over. This is like reviewing notes basically.

Also, you can manually advance repetitions if needed, for example before an exam.

It works very well for me and I constantly have to (and want to) learn lots of stuff.