Can I go if my sister is married (my sister is not married yet)

Generally speaking, when an elder sister gets married, she can attend. This represents the family's respect and blessing for the sister's marriage. Of course, whether you can attend the wedding may depend on the local culture and customs.

Some places may have traditional customs, for example, some religions or regions may stipulate that unmarried women cannot attend weddings. But generally speaking, as long as there is no contradiction or special circumstances between family members, the elder sister can attend the younger sister's wedding.

If my sister can't attend for some reason, she can also express her wishes for her marriage in other ways, such as writing a blessing letter or sending a blessing through video call.