First experience rolling

Last night around 10 i took half a pill (140mg) it didnt kick in two hours later and i went to sleep. Then at around 3am i woke up it hit. I plan to do more next weekend (im aware of the 3 month rule but after next weekend i wont be rolling again until april.) since it took around five hours too kick in this time will it be the same next weekend? Because i wont want to have to get the bus home alone at the peak of my roll as thats when my pupils get largest and i get quite anxious going home high. Next weekend i think im doing crystal instead of ecstasy so ill be snorting it but idk if itll hit faster or not and if itll ware off faster.