No problem and I'm allowing some classes FROM 3.5 I prefer their bard, monk, druid, sorceror and ranger just the rules I have are 3.0 so that is what I must use for most of it.
For example the Forgotten Realms Book is 3.0, all my core books 3.0 so have to use 3.0 its just I'm not buying 3.5 after buying lots of 3.0 rules.
You can run 3.5 I have those rules on-line for free to play a character so if your willing to GM a game there let me know.
So we have one Mage, and yes you will have to roll dice I'm old school that way when this starts up. Normally I do 4d6 drop the lowest die re-rolling 1's rolling in order. If your a specific class you can opt not to roll for that and take an automatic 16 instead of rolling n one stat. Then if your Con is under 10 you raise it to 10, before racial modifiers. This makes sure you get a basic class you like with a good stat, at least an average Con in most cases and you won't all put the lowest stat into Cha.