I was wondering is it normal that i can't open up my mouth like i used to before having my wisdom tooth removed?

Difficulty opening: If this was within the last week or so, it's not uncommon and will most likely subside over time. Longer than that, speak to the dentist who treated you. There are things that can be done to speed recovery back to normal.

Yes, but: Yes, but after a week or so, your opening should return to normal. If it persists, there may be a number of issues. See your oral surgeon for evaluation.