If you are an adult (according to Allah) like 25-26, but a child according to society and your family, and you want to get married for Islamic reasons (keeping away from zinnah) and both the man and woman agrees, i know you should get the permission of the parents but they are ignorant on these matters as they have been strongly swayed by todays customs (may Allah guide us all) and believe one must get a degree and buy a house then by age 28 go get married, and before then suppress our sexual desires or even secretly relieve them.
It is genuinely just a "hassle and stress" to ask permission, so what i am suggesting is would it be ok if they got married for the sake of a halal relationship? Is the consent of a "wali" compulsory for the girl? The girl is shia and boy is hanafi sunni. Both intend to follow their religion after getting married (no one is converting and will respect each other's religion)