Dear,
how can one answer this question?
If you are smart enough, willing to study and learn, hard worker, motivated and responcible,then I belive you will be able to handle any job ( By any I mean ANY even not Oracle related and even not IT related - say become a marketing manager)
"I work on Oracle 8.1.7 on Windows" could mean that you use RMAN to make hot backups, you have made lots of performance tununing etc. what would mean you are a good dba, and also could mean that you have imported from time to time some dmp provided to you, what would mean that you have no idea what's going on.
From your post I would say that you are not very experienced, so it is up to you if you want to take the challange, spend several hard monts studing, reading trough the nights etc. or not. Especially if you are not the only DBA but a junior member of a DBA team, then I do not see any other issue here, than the question do you really want to do it or not