I have been living in Estonia for six years. My Estonian is not great, although I have been learning over these years. English is all I can use if I want to speak fluently to ask for things at the shop, pharmacy, doctor, hospital and even directions. I have found out that most young people speak it to a reasonable level in Tallinn and towns like Tartu and Pärnu. Older people speak it a bit less, but they will still make an effort if you need to communicate. In a business setting, for sure people speak even more English, especially if you work in a sector such as IT.
Of course, I recommend that you try to learn the Estonian language as there are plenty of places to do so, but it’s a task that would take time. In the meantime, English should be fine.