This is the problem faced by many, so you are not alone. Sadly, condom size and penis size don't match in many cases. Condom manufacturers produce condoms based on approved sizes, which are usually longer than the average penis length. The biggest problem with condom fit is the girth (circumference) size. As long as the girth is a perfect fit for you, you can use the condom as the chances of slipping off are less.
If the extra materials bunch up and bother you, you can use an erection ring or vibrating ring on top of the condom to curb the bagginess at the base. You can also choose a simple erection ring. If you are still bothered, you can alternatively ask your partner to wear a female condom and you can perform without that extra-long condom.
If you are very particular about knowing your size, we insist you to refer size chart at www.condombazaar.com/sizechart