Not Everyone Can Deadlift
Not everyone is able to deadlift off the floor with a straight bar. It could because of mobility issues, previous injuries, limb length or other reasons. The deadlift is a great exercise, but there isn't a exercise that is essential. The standard height we deadlift from is only that height because that's the height the weight plates happen to be. There isn't any other reason.
If you're not able to get into a good starting position when deadifting off the floor, there are other variations you can try,
Trap Bar Deadlift With High Handles
This is is a common variation I use with clients who aren't able to deadlift. I've had clients in their seventies who struggled with their mobility when they started with me, still managed to use to do trap bar deadlifts with high handles.
This is a link to an article about trap bar deadlifts
Romanian Deadlifts
Romanian deadlifts are perfect for people who lack the mobility to do deadifts from the floor, as they start at the top and only go down as low as your mobility allows while training the hip hinge and your posterior chain.
This is a link to an article about Romanian Deadlifts
Rack Pulls
Rack pulls are the same as deadlifts, but instead of pulling from the floor, you pull from the safety bars in a rack. You'll set the bar as low as your mobility allows. This will often be shin height but can be higher if needed.
Deadlift on Blocks
These are just like rack pulls, but instead of doing it from the safety pins in a rack, you do on blocks. Most people will be able to get in a good setup position with the bar starting higher.
Don't force yourself to do an exercise that you're not able to do and find variations you can do. If you want, you can work on being able to do it from the floor while you do these variation.
If you're not able to get into a good starting position when deadifting off the floor, there are other variations you can try,
Trap Bar Deadlift With High Handles
This is is a common variation I use with clients who aren't able to deadlift. I've had clients in their seventies who struggled with their mobility when they started with me, still managed to use to do trap bar deadlifts with high handles.
This is a link to an article about trap bar deadlifts
Romanian Deadlifts
Romanian deadlifts are perfect for people who lack the mobility to do deadifts from the floor, as they start at the top and only go down as low as your mobility allows while training the hip hinge and your posterior chain.
This is a link to an article about Romanian Deadlifts
Rack Pulls
Rack pulls are the same as deadlifts, but instead of pulling from the floor, you pull from the safety bars in a rack. You'll set the bar as low as your mobility allows. This will often be shin height but can be higher if needed.
Deadlift on Blocks
These are just like rack pulls, but instead of doing it from the safety pins in a rack, you do on blocks. Most people will be able to get in a good setup position with the bar starting higher.
Don't force yourself to do an exercise that you're not able to do and find variations you can do. If you want, you can work on being able to do it from the floor while you do these variation.